Ethylene separation with temperature swing adsorption

ABSTRACT

A process for component separation in a polymer production system, comprising (a) separating a polymerization product stream into a gas stream and a polymer stream, (b) contacting the polymer stream with a purge gas to yield a purged polymer and a spent purge gas comprising purge gas, ethylene, and ethane, (c) contacting the spent purge gas with a temperature swing adsorber contactor (TSAC) to yield a loaded TSAC, wherein at least a portion of the ethylene is adsorbed by the TSAC at a first temperature to yield TSAC-adsorbed ethylene, wherein a portion of the ethane is adsorbed by the TSAC at the first temperature to yield TSAC-adsorbed ethane, (d) heating the loaded TSAC to a second temperature to yield a regenerated TSAC, and (e) contacting the regenerated TSAC with a sweeping gas stream to yield a recovered adsorbed gas stream comprising sweeping gas, recovered ethylene and recovered ethane.

TECHNICAL FIELD

The present disclosure generally relates to the production ofpolyethylene. More specifically, this disclosure relates to a processfor improving polyethylene production efficiency by recovering unreactedethylene.

BACKGROUND

The production of polymers such as polyethylene from light gasesrequires a high purity feedstock of monomers and comonomers. Due to thesmall differences in boiling points between the light gases in such afeedstock, industrial production of a high purity feedstock can requirethe operation of multiple distillation columns, high pressures, andcryogenic temperatures. As such, the energy costs associated withfeedstock purification represent a significant proportion of the totalcost for the production of such polymers. Further, the infrastructurerequired for producing, maintaining, and recycling high purity feedstockis a significant portion of the associated capital cost.

In order to offset some of the costs and maximize production, it can beuseful to reclaim and/or recycle any unreacted feedstock gases,especially the light hydrocarbon reactants, such as ethylene. Gasescomprising unreacted monomers can be separated from the polymer afterthe polymerization reaction. The polymer is processed while theunreacted monomers are recovered from the gases that are reclaimedfollowing the polymerization reaction. To accomplish this, the reclaimedgas streams have conventionally either been routed through apurification process or redirected through other redundant processingsteps. In either case, conventional processes of recovering monomer(e.g., unreacted ethylene) have necessitated energetically unfavorableand expensive processes. Thus, there is an ongoing need for developingefficient processes for the recovery of unreacted ethylene duringpolyethylene production.

BRIEF SUMMARY

Disclosed herein is a process for component separation in a polymerproduction system, comprising (a) separating a polymerization productstream into a gas stream and a polymer stream, wherein the polymerstream comprises polyethylene, ethylene and ethane, (b) contacting atleast a portion of the polymer stream with a purge gas to yield a purgedpolymer stream and a spent purge gas stream, wherein the purged polymerstream comprises polyethylene, and wherein the spent purge gas comprisespurge gas, ethylene, and ethane, (c) contacting at least a portion ofthe spent purge gas stream with a temperature swing adsorber contactor(TSAC) to yield a loaded TSAC and a non-adsorbed gas stream, wherein atleast a portion of the ethylene is adsorbed by the TSAC at a firsttemperature to yield TSAC-adsorbed ethylene, wherein a portion of theethane is adsorbed by the TSAC at the first temperature to yieldTSAC-adsorbed ethane, and wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane, (d) heating at least aportion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, and wherein the desorbed ethane comprises at least a portionof the TSAC-adsorbed ethane, and (e) contacting at least a portion ofthe regenerated TSAC with a sweeping gas stream to yield a recoveredadsorbed gas stream, wherein the recovered adsorbed gas stream comprisessweeping gas, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.

Further disclosed herein is a process for ethylene recovery from adilute ethylene stream in a polyethylene production system, comprising(a) providing a dilute ethylene stream comprising ethylene and ethane,wherein a pressure of the dilute ethylene stream is from about 100 kPato about 150 kPa, wherein ethylene is characterized by a partialpressure of less than about 10 kPa, and wherein ethane is characterizedby a partial pressure of less than about 5 kPa, (b) contacting thedilute ethylene stream with a temperature swing adsorber contactor(TSAC) to yield a loaded TSAC and a non-adsorbed gas stream, wherein atleast a portion of the ethylene is adsorbed by the TSAC at a firsttemperature to yield TSAC-adsorbed ethylene, wherein a portion of theethane is adsorbed by the TSAC at the first temperature to yieldTSAC-adsorbed ethane, wherein the loaded TSAC comprises TSAC-adsorbedethylene and TSAC-adsorbed ethane, and wherein the TSAC is characterizedby an adsorption selectivity of ethylene versus ethane at the firsttemperature of equal to or greater than about 5, (c) heating at least aportion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, wherein the desorbed ethane comprises at least a portion ofthe TSAC-adsorbed ethane, and wherein the second temperature is greaterthan the first temperature by equal to or greater than about 10° C., and(d) contacting at least a portion of the regenerated TSAC with asweeping gas stream to yield a recovered adsorbed gas stream, whereinthe recovered adsorbed gas stream comprises a sweeping gas, recoveredethylene and recovered ethane, wherein the recovered ethylene comprisesat least a portion of the desorbed ethylene, and wherein the recoveredethane comprises at least a portion of the desorbed ethane.

Also disclosed herein is a process for ethylene polymerization,comprising (a) polymerizing ethylene in a slurry loop reactor system toobtain a polymerization product stream, (b) separating a polymerizationproduct stream in a flash chamber into a gas stream and a polymer streamcomprising polyethylene, ethylene and ethane, (c) contacting at least aportion of the polymer stream with a purge gas in a purge column toyield a purged polymer stream and a spent purge gas stream, wherein thepurged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises nitrogen, ethylene, and ethane, (d) contacting atleast a portion of the spent purge gas stream with a temperature swingadsorber contactor (TSAC) to yield a loaded TSAC and a non-adsorbed gasstream, wherein at least a portion of the ethylene is adsorbed by theTSAC at a first temperature to yield TSAC-adsorbed ethylene, wherein aportion of the ethane is adsorbed by the TSAC at the first temperatureto yield TSAC-adsorbed ethane, wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane, and wherein the TSAC ischaracterized by an adsorption selectivity of ethylene versus ethane atthe first temperature of equal to or greater than about 5, (e) heatingat least a portion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, wherein the desorbed ethane comprises at least a portion ofthe TSAC-adsorbed ethane, and wherein the second temperature is greaterthan the first temperature by equal to or greater than about 10° C., and(f) contacting at least a portion of the regenerated TSAC witholefin-free isobutane to yield a recovered adsorbed gas stream, whereinthe recovered adsorbed gas stream comprises isobutane, recoveredethylene and recovered ethane, wherein the recovered ethylene comprisesat least a portion of the desorbed ethylene, and wherein the recoveredethane comprises at least a portion of the desorbed ethane.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of the preferred embodiments of the disclosedprocesses and systems, reference will now be made to the accompanyingdrawings in which:

FIG. 1 illustrates a schematic of an embodiment of a polyethyleneproduction system;

FIG. 2 illustrates a flow diagram of an embodiment of a polyethyleneproduction process;

FIG. 3 illustrates a schematic of an embodiment of a slurry loop reactorsystem;

FIG. 4A illustrates a schematic of an isometric view of a hollow fibercontactor; and

FIG. 4B illustrates a schematic of a side view of a hollow fibercontactor.

DETAILED DESCRIPTION

It should be understood at the outset that although an illustrativeimplementation of one or more embodiments are provided below, thedisclosed systems and/or methods can be implemented using any number oftechniques, whether currently known or in existence. The disclosureshould in no way be limited to the illustrative implementations,drawings, and techniques illustrated below, including the exemplarydesigns and implementations illustrated and described herein, but can bemodified within the scope of the appended claims along with their fullscope of equivalents.

Disclosed herein are systems, apparatuses, and processes related topetrochemical production processes, for example the production ofpolyethylene. The systems, apparatuses, and processes are generallyrelated to the separation of a first chemical component or compound(e.g., unreacted monomer, unreacted ethylene) from a compositionresulting from petrochemical production processes, for example theproduction of polyethylene, and comprising the first chemical componentor compound and one or more other chemical components, compounds, or thelike.

In an embodiment, a process for component separation in a polymerproduction system (e.g., polyethylene production system) can generallycomprise the steps of (a) separating a polymerization product streaminto a gas stream and a polymer stream, wherein the polymer streamcomprises polyethylene, ethylene (e.g., unreacted ethylene) and ethane;(b) contacting at least a portion of the polymer stream with a purge gasto yield a purged polymer stream and a spent purge gas stream, whereinthe purged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises purge gas, ethylene, and ethane; (c) contacting atleast a portion of the spent purge gas stream with a temperature swingadsorber contactor (TSAC) to yield a loaded TSAC and a non-adsorbed gasstream, wherein at least a portion of the ethylene is adsorbed by theTSAC at a first temperature to yield TSAC-adsorbed ethylene, wherein aportion of the ethane is adsorbed by the TSAC at the first temperatureto yield TSAC-adsorbed ethane, and wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane; (d) heating at least aportion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, and wherein the desorbed ethane comprises at least a portionof the TSAC-adsorbed ethane; and (e) contacting at least a portion ofthe regenerated TSAC with a sweeping gas stream to yield a recoveredadsorbed gas stream, wherein the recovered adsorbed gas stream comprisessweeping gas, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.

In an embodiment, a process for component separation in a polymerproduction system (e.g., polyethylene production system) can generallycomprise selectively separating a first hydrocarbon (e.g., unreactedmonomer, unreacted ethylene) from a second hydrocarbon (e.g., by-producthydrocarbon, by-product ethane), wherein the first hydrocarbon and thesecond hydrocarbon can be recovered from a polymerization productstream. While the present disclosure will be discussed in detail in thecontext of a process for selectively separating hydrocarbons in apolyethylene production system, it should be understood that suchprocess or any steps thereof can be applied in any suitablepetrochemical production process requiring selective separation ofhydrocarbons. The hydrocarbons can comprise any suitable hydrocarbonscompatible with the disclosed methods and materials.

Referring to the embodiment of FIG. 1, a polyethylene production (PEP)system 1000 is disclosed. PEP system 1000 generally comprises a slurryloop reactor system 100, a flash chamber 200, a heavy distillationcolumn 300, a light distillation column 350, a purge column 400, atemperature swing adsorption (TSA) unit 500, and an isobutane (i-butane)and nitrogen recovery unit (INRU) 600. In the PEP embodiments disclosedherein, various system components can be in fluid communication via oneor more conduits (e.g., pipes, tubing, flow lines, etc.) suitable forthe conveyance of a particular stream, for example as shown in detail bythe numbered streams in FIG. 1.

In an embodiment, a reagents stream 110 (also referred to as a feedstream) can be communicated to the slurry loop reactor system 100. Apolymerization product stream 120 can be communicated from the slurryloop reactor system 100 to the flash chamber 200. A gas stream 210 canbe communicated from the flash chamber 200 to the heavy distillationcolumn 300. In some embodiments, the heavy distillation column 300 canbe referred to as a first distillation column. A heavy distillationbottoms stream 310 can be emitted from the heavy distillation column300, and a heavy distillation side stream 320 can be emitted from theheavy distillation column 300. An intermediate hydrocarbon stream 330can be emitted from the heavy distillation column 300 and communicatedto the light distillation column 350. In some embodiments, the lightdistillation column 350 can be referred to as a second distillationcolumn. A light hydrocarbon stream 380 can be emitted from the lightdistillation column 350, and a light distillation side stream 370 can beemitted from the light distillation column 350. A light distillationbottoms stream 360 comprising olefin-free isobutane 365 can be emittedfrom the light distillation column 350. A polymer stream 220 can becommunicated from the flash chamber 200 to the purge column 400. A purgegas stream 410 can be communicated to the purge column 400. A purgedpolymer stream 420 comprising a polymer 425 can be emitted from thepurge column 400. A spent purge gas stream 430 can be communicated fromthe purge column 400 to the TSA unit 500. A sweeping gas stream 510 canbe communicated to the TSA unit 500. At least a portion of theolefin-free isobutane 365 can be recycled 366 to the TSA unit 500, forexample via the sweeping gas stream 510. A recovered adsorbed gas stream530 comprising isobutane and ethylene 535 can be emitted from the TSAunit 500. At least a portion of the isobutane and ethylene 535 can berecycled 536 to the slurry loop reactor system 100, for example via thereagents stream 110. A non-adsorbed gas stream 520 can be communicatedfrom the TSA unit 500 to the INRU 600. A gas stream 610 comprisingnitrogen 615 can be emitted from the INRU 600. At least a portion of thenitrogen 615 can be recycled 616 to the purge column 400, for examplevia the purge gas stream 410. A gas stream 620 comprising isobutane andethane 625 can be emitted from the INRU 600. At least a portion of theisobutane and ethane 625 can be recycled to one or more distillationcolumns. For example, at least a portion of the isobutane and ethane 625can be recycled 626 to the heavy distillation column 300, for examplevia the gas stream 210.

For purposes of the disclosure herein an “olefin-free” hydrocarbon(e.g., olefin-free isobutane) refers to a hydrocarbon (e.g., isobutane)that can be free of olefins, alternatively, substantially free ofolefins, alternatively, essentially free of olefins, or alternatively,consist or consist essentially of non-olefins. For example, olefins canbe present in an olefin-free hydrocarbon (e.g., olefin-free isobutane)in an amount of less than about 10% by total weight of the olefin-freehydrocarbon, alternatively, less than about 9%, alternatively, less thanabout 8%, alternatively, less than about 7%, alternatively, less thanabout 6%, alternatively, less than about 5%, alternatively, less thanabout 4%, alternatively, less than about 3%, alternatively, less thanabout 2%, alternatively, less than about 1.0%, alternatively, less thanabout 0.5%, alternatively, less than about 0.1%.

Embodiments of a suitable PEP system having been disclosed, embodimentsof a PEP process are now disclosed. One or more of the embodiments of aPEP process can be described with reference to one or more embodimentsof PEP system 1000. Although a given PEP process can be described withreference to one or more embodiments of a PEP system, such a disclosureshould not be construed as so-limiting. Although the various steps ofthe processes disclosed herein may be disclosed or illustrated in aparticular order, such should not be construed as limiting theperformance of these processes to any particular order unless otherwiseindicated.

Referring to the embodiment of FIG. 2, a PEP process 2000 isillustrated. PEP process 2000 can generally comprise (i) a step 2100 ofpurifying a feed stream; (ii) a step 2200 of polymerizing monomers ofthe purified feed stream to form a polymerization product stream; (iii)a step 2300 of separating the polymerization product stream into apolymer stream and a gas stream; (iv) a step 2400 of processing the gasstream in one or more distillation columns; (v) a step 2500 of purgingthe polymer stream to produce a purged polymer stream and a spent purgegas stream; (vi) a step 2600 of contacting the spent purge gas streamwith a temperature swing adsorber contactor (TSAC) to yield a loadedTSAC and a non-adsorbed gas stream; (vii) a step 2700 of heating theloaded TSAC to yield a regenerated TSAC; (viii) a step 2800 ofcontacting the regenerated TSAC with a sweeping gas stream to yield arecovered adsorbed gas stream; and (ix) a step 2900 of separating thenon-adsorbed gas stream into a nitrogen stream and an isobutane andethane stream.

In an embodiment, the PEP process 2000 or a portion thereof can beimplemented via the PEP system 1000 (e.g., as illustrated in FIG. 1).

In an embodiment, the PEP process 2000 can generally comprise the step2100 of purifying a feed stream or a reagents stream. In one or more ofthe embodiments disclosed herein, purifying a feed stream can compriseseparating unwanted compounds and elements from a feed stream comprisingethylene to form a purified feed stream. In an embodiment, purifying afeed stream can comprise any suitable method or process, including thenon-limiting examples of filtering, membrane screening, reacting withvarious chemicals, absorbing, adsorbing, distillation(s), orcombinations thereof.

Referring to the embodiment of FIG. 3, a feed stream 10 (e.g., reagentsstream 110 in the embodiment of FIG. 1) can be communicated to apurifier 102. In an embodiment, the feed stream 10 can comprise ethyleneand various other gases, such as but not limited to methane, ethane,acetylene, propane, propylene, water, nitrogen, oxygen, various othergaseous hydrocarbons having three or more carbon atoms, variouscontaminants, or combinations thereof. In one or more of the embodimentsdisclosed herein, the purifier 102 can comprise a device or apparatussuitable for the purification of one or more reactant gases in a feedstream comprising a plurality of potentially unwanted gaseous compounds,elements, contaminants, and the like. Non-limiting examples of asuitable purifier 102 can comprise a filter, a membrane, a reactor, anabsorbent, a molecular sieve, one or more distillation columns, orcombinations thereof. The purifier 102 can be configured to separateethylene from a stream comprising a plurality of potentially unwantedgaseous compounds, elements, contaminants, and the like.

In an embodiment, purifying a feed stream can yield a purified feedstream 11 comprising substantially pure monomers (e.g., substantiallypure ethylene). In an embodiment, the purified feed stream can compriseless than about 25% by total weight of the stream, alternatively, lessthan about 10%, alternatively, less than about 1.0% of any one or moreof nitrogen, oxygen, methane, ethane, propane, comonomers, orcombinations thereof. As used herein “substantially pure ethylene”refers to a fluid stream comprising at least about 60% ethylene,alternatively, at least about 70% ethylene, alternatively, at leastabout 80% ethylene, alternatively, at least about 90% ethylene,alternatively, at least about 95% ethylene, alternatively, at leastabout 99% ethylene by total weight of the stream, alternatively, atleast about 99.5% ethylene by total weight of the stream. In anembodiment, the feed stream 11 can further comprise trace amounts ofethane, for example, as from a recycled stream, as will be discussed inmore detail later herein.

In some embodiments, the purified feed stream can comprise a comonomer,such as unsaturated hydrocarbons having from 3 to 20 carbon atoms.Nonlimiting examples of comonomers that can be present in the purifiedfeed stream include alpha olefins, such as for example propylene,1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 4-methyl-1-pentene,1-heptene, 1-octene, 1-nonene, 1-decene, and the like, or combinationsthereof.

In an embodiment, the PEP process 2000 can generally comprise the step2200 of polymerizing monomers of the purified feed stream to form apolymerization product stream. The polymerization product stream can beformed using any suitable olefin polymerization method which can becarried out using various types of polymerization reactors.

As used herein, the terms “polymerization reactor” or “reactor” includeany polymerization reactor capable of polymerizing olefin monomers orcomonomers to produce homopolymers or copolymers. Such homopolymers andcopolymers are referred to as resins or polymers. The various types ofreactors include those that can be referred to as batch, slurry, tubularor autoclave reactors. Slurry reactors can comprise vertical orhorizontal loops. Reactor types can include batch or continuousprocesses. Continuous processes could use intermittent or continuousproduct discharge. Processes can also include partial or full directrecycle of unreacted monomer, unreacted comonomer, and/or diluent.

Polymerization reactor systems of the present disclosure can compriseone type of reactor in a system or multiple reactors of the same ordifferent type. Production of polymers in multiple reactors can includeseveral stages in at least two separate polymerization reactorsinterconnected by transfer stream(s), line(s), apparatus(es) (forexample, a separation vessel(s)) and/or device(s) (for example, a valveor other mechanism) making it possible to transfer the polymersresulting from a first polymerization reactor into a second reactor. Thedesired polymerization conditions in one of the reactors can bedifferent from the operating conditions of the other reactors.Alternatively, polymerization in multiple reactors can include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems can include anycombination including, but not limited to, multiple loop reactors. Themultiple reactors can be operated in series or in parallel.

According to one aspect of this disclosure, the polymerization reactorsystem can comprise at least one loop slurry reactor comprising verticalor horizontal loops. Monomer, diluent, catalyst, and optionally anycomonomer can be continuously fed to a loop reactor where polymerizationoccurs. Generally, continuous processes can comprise the continuousintroduction of a monomer, an optional comonomer, a catalyst, and adiluent into a polymerization reactor and the continuous removal fromthis reactor of a suspension comprising polymer particles and thediluent. Reactor effluent can be flashed to remove the solid polymerfrom the liquids that comprise the diluent, monomer and/or comonomer.Various technologies can be used for this separation step including butnot limited to, flashing that can include any combination of heataddition and pressure reduction; separation by cyclonic action in eithera cyclone or hydrocyclone; or separation by centrifugation.

A suitable slurry polymerization process (also known as the particleform process), is disclosed, for example, in U.S. Pat. Nos. 3,248,179;4,501,885; 5,565,175; 5,575,979; 6,239,235; 6,262,191; and 6,833,415;each of which is incorporated by reference herein in its entirety.

In one or more embodiments, suitable diluents used in slurrypolymerization include, but are not limited to, the monomer, andoptionally, the comonomer, being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

Polymerization reactors suitable for the disclosed systems and processescan further comprise any combination of at least one raw material feedsystem, at least one feed system for catalyst or catalyst components,and/or at least one polymer recovery system. Suitable reactor systemscan further comprise systems for feedstock purification, catalyststorage and preparation, extrusion, reactor cooling, polymer recovery,fractionation, recycle, storage, loadout, laboratory analysis, andprocess control.

Conditions (e.g., polymerization conditions) that are controlled forpolymerization efficiency and to provide resin properties includetemperature, pressure, type and/or quantity of catalyst or co-catalyst,and concentrations and/or partial pressures of various reactants.

Polymerization temperature can affect catalyst productivity, polymermolecular weight and molecular weight distribution. Suitablepolymerization temperature can be any temperature below thede-polymerization temperature according to the Gibbs Free energyequation. Typically this includes from about 60° C. to about 280° C.,for example, and from about 70° C. to about 110° C., depending upon thetype of polymerization reactor.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than about 1,000 psig. Polymerizationreactors can also be operated in a supercritical region occurring atgenerally higher temperatures and pressures. Operation above thecritical point of a pressure/temperature diagram (supercritical phase)can offer advantages. In an embodiment, polymerization can occur in anenvironment having a suitable combination of temperature and pressure.For example, polymerization can occur at a pressure in a range of fromabout 550 psi to about 650 psi, alternatively, from about 600 psi toabout 625 psi and a temperature in a range of from about 170° F. toabout 230° F., alternatively, from about 195° F. to about 220° F.

The concentration of various reactants can be controlled to produceresins with certain physical and mechanical properties. The proposedend-use product that will be formed by the resin and the method offorming that product determines the desired resin properties. Mechanicalproperties include tensile, flexural, impact, creep, stress relaxationand hardness tests. Physical properties include density, molecularweight, molecular weight distribution, melting temperature, glasstransition temperature, temperature melt of crystallization, density,stereoregularity, crack growth, long chain branching and rheologicalparameters.

The concentrations and/or partial pressures of monomer, comonomer,hydrogen, co-catalyst, modifiers, and electron donors are important inproducing these resin properties. Comonomer can be used to controlproduct density. Hydrogen can be used to control product molecularweight. Cocatalysts can be used to alkylate, scavenge poisons andcontrol molecular weight. Modifiers can be used to control productproperties and electron donors affect stereoregularity, the molecularweight distribution, or molecular weight. In addition, the concentrationof poisons is minimized because poisons impact the reactions and productproperties.

In an embodiment, any suitable catalyst system can be employed. Asuitable catalyst system can comprise a catalyst and, optionally, aco-catalyst (e.g., organoaluminum compound) and/or promoter.Non-limiting examples of suitable catalyst systems include Ziegler Nattacatalysts, Ziegler catalysts, chromium catalysts, chromium oxidecatalysts, chromocene catalysts, metallocene catalysts, nickelcatalysts, or combinations thereof. Catalyst systems suitable for use inthe present disclosure have been described, for example, in U.S. Pat.No. 7,619,047 and U.S. Patent Application Publication Nos. 2007/0197374,2009/0004417, 2010/0029872, 2006/0094590, and 2010/0041842, each ofwhich is incorporated by reference herein in its entirety.

In an embodiment of the present disclosure, the catalyst system cancomprise an activator. The activator can be a solid oxideactivator-support, a chemically treated solid oxide, a clay mineral, apillared clay, an exfoliated clay, an exfoliated clay gelled intoanother oxide matrix, a layered silicate mineral, a non-layered silicatemineral, a layered aluminosilicate mineral, a non-layeredaluminosilicate mineral, an aluminoxane, a supported aluminoxane, anionizing ionic compound, an organoboron compound, or any combinationthereof. The terms “chemically-treated solid oxide,” “solid oxideactivator-support,” “acidic activator-support,” “activator-support,”“treated solid oxide compound,” and the like are used herein to indicatea solid, inorganic oxide of relatively high porosity, which exhibitsLewis acidic or Brønsted acidic behavior, and which has been treatedwith an electron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide compound comprises the calcined contact product of at leastone solid oxide compound with at least one electron-withdrawing anionsource compound. Typically, the chemically-treated solid oxide comprisesat least one ionizing, acidic solid oxide compound. The terms “support”and “activator-support” are not used to imply these components areinert, and such components should not be construed as an inert componentof the catalyst composition.

In one or more of the embodiments disclosed herein, monomers in a feedstream (e.g., purified feed stream 11) can be polymerized. In one ormore embodiments, polymerizing monomers of the purified feed stream cancomprise allowing a polymerization reaction between a plurality ofmonomers by contacting a monomer or monomers with a catalyst systemunder conditions suitable for the formation of a polymer. In one or moreof the embodiments disclosed herein, polymerizing comonomers of thepurified feed stream can comprise allowing a polymerization reactionbetween a plurality of comonomers by contacting a comonomer orcomonomers with a catalyst system under conditions suitable for theformation of a copolymer.

In an aspect of this disclosure, the step 2200 of polymerizing monomersof the purified feed stream to form a polymerization product stream canbe carried out using a slurry loop reactor system, such as for example aslurry loop reactor system 101 illustrated in the embodiment of FIG. 3.The slurry loop reactor system 101 generally comprises a purifier 102, afirst reactor 104, and a second reactor 106. In the slurry loop reactorsystem embodiments disclosed herein, various system components can be influid communication via one or more conduits (e.g., pipes, tubing, flowlines, etc.) suitable for the conveyance of a particular stream, forexample as shown in detail by the numbered streams in FIG. 3.

In an embodiment, a purified feed stream 11 can be communicated from thepurifier 102 to one or more of the reactors (e.g., a first reactor 104,a second reactor 106). Where the slurry loop reactor system comprisestwo or more reactors, a mid-polymerization reactor stream 15 can becommunicated from the first reactor 104 to the second reactor 106.Hydrogen can be introduced into the second reactor 106 in stream 21. Apolymerization product stream (e.g., polymerization product stream 121in FIG. 3, polymerization product stream 120 in FIG. 1) can be emittedfrom the first reactor 104 and/or the second reactor 106.

In embodiments as illustrated by FIG. 3, polymerizing monomers of thepurified feed stream can comprise routing the purified feed stream 11 tothe one or more of the polymerization reactors 104, 106. Polymerizingmonomers of the mid-polymerization reactor stream 15 can compriserouting the mid-polymerization reactor stream 15 to polymerizationreactor(s) 106. In embodiments as illustrated by FIG. 3, polymerizingmonomers of the mid-polymerization reactor stream 15 can compriserouting the mid-polymerization reactor stream 15 from polymerizationreactor(s) 104 to polymerization reactor(s) 106.

In one or more of the embodiments disclosed herein, the polymerizationreactors 104, 106 can comprise any vessel or combination of vesselssuitably configured to provide an environment for a chemical reaction(e.g., a contact zone) between monomers (e.g., ethylene) and/or polymers(e.g., an “active” or growing polymer chain), and optionally comonomersand/or copolymers, in the presence of a catalyst to yield a polymer(e.g., a polyethylene polymer) and/or copolymer. Although theembodiments illustrated in FIG. 3 illustrate a PEP system having tworeactors in series, one of skill in the art viewing this disclosure willrecognize that one reactor, alternatively, any suitable number and/orconfiguration of reactors, can be employed.

In embodiments as illustrated in FIG. 3, production of polymers inmultiple reactors can include at least two polymerization reactors 104,106 interconnected by one or more devices or apparatus (e.g., valve,continuous take-off valve, and/or continuous take-off mechanism). Inembodiments as illustrated in FIG. 3, production of polymers in multiplereactors can include at least two polymerization reactors 104, 106interconnected by one or more streams or lines (e.g., mid-polymerizationreactor stream 15). In some embodiments, production of polymers inmultiple reactors can include at least two polymerization reactors 104,106 interconnected by one or more separators (e.g., flash chambers).

In an embodiment, polymerizing monomers can comprise introducing asuitable catalyst system into the first and/or second reactor 104, 106,respectively, so as to form a slurry. Alternatively, a suitable catalystsystem can reside in the first and/or second reactor 104, 106,respectively.

As previously described herein, polymerizing monomers can compriseselectively manipulating one or more polymerization reaction conditionsto yield a given polymer product, to yield a polymer product having oneor more desirable properties, to achieve a desired efficiency, toachieve a desired yield, the like, or combinations thereof. In anembodiment, polymerizing monomers of the purified feed stream 11 cancomprise adjusting one or more polymerization reaction conditions.

In an embodiment, polymerizing monomers can comprise maintaining asuitable temperature, pressure, and/or partial pressure(s) during thepolymerization reaction, alternatively, cycling between a series ofsuitable temperatures, pressures, and/or partial pressure(s) during thepolymerization reaction.

In an embodiment, polymerizing monomers can comprise polymerizingcomonomers in one or more of polymerization reactors 104, 106. In anembodiment, polymerizing monomers can comprise introducing ethylenemonomer and/or a comonomer to the polymerization reactor 106.

In an embodiment, polymerizing monomers can include introducing hydrogeninto one or more of reactors 104 and 106. For example, FIG. 3illustrates hydrogen can be introduced into reactor 106 through stream21. The amount of hydrogen introduced into the reactor 106 can beadjusted so as to obtain, in the diluent, a molar ratio of hydrogen toethylene of 0.001 to 0.1. This molar ratio can be at least 0.004 inreactor 106. In some embodiments, this molar ratio cannot exceed 0.05.The ratio of the concentration of hydrogen in the diluent in reactor 104to the concentration of hydrogen polymerization reactor 106 can be atleast 20, alternatively, at least 30, alternatively, at least 40,alternatively, not greater than 300, alternatively, not greater than200. Suitable hydrogen concentration control methods and systems aredisclosed in U.S. Pat. No. 6,225,421, which is incorporated by referenceherein in its entirety.

In an embodiment, polymerizing monomers can comprise circulating,flowing, cycling, mixing, agitating, or combinations thereof, themonomers (optionally, comonomers), catalyst system, and/or the slurrywithin and/or between the reactors 104, 106. In an embodiment where themonomers (optionally, comonomers), catalyst system, and/or slurry arecirculated, circulation can be at a velocity (e.g., slurry velocity) offrom about 1 m/s to about 30 m/s, alternatively, from about 2 m/s toabout 17 m/s, or alternatively, from about 3 m/s to about 15 m/s.

In some embodiments, polymerizing monomers can comprise configuringreactors 104, 106 to yield an unimodal resin. Herein, the “modality” ofa polymer resin refers to the form of its molecular weight distributioncurve, i.e., the appearance of the graph of the polymer weight fractionas a function of its molecular weight. The polymer weight fractionrefers to the weight fraction of molecules of a given size. A polymerhaving a molecular weight distribution curve showing a single peak canbe referred to as a unimodal polymer, a polymer having curve showing twodistinct peaks can be referred to as bimodal polymer, a polymer having acurve showing three distinct peaks can be referred to as trimodalpolymer, etc.

In other embodiments, polymerizing monomers can comprise configuringreactors 104, 106 to yield a multimodal (e.g., a bimodal) polymer (e.g.,polyethylene). For example, the resultant polymer can comprise both arelatively high molecular weight, low density (HMWLD) polyethylenepolymer and a relatively low molecular weight, high density (LMWHD)polyethylene polymer. For example, various types of suitable polymerscan be characterized as having a various densities. For example, a TypeI can be characterized as having a density in a range of from about0.910 g/cm³ to about 0.925 g/cm³, alternatively, a Type II can becharacterized as having a density from about 0.926 g/cm³ to about 0.940g/cm³, alternatively, a Type III can be characterized as having adensity from about 0.941 g/cm³ to about 0.959 g/cm³, alternatively, aType IV can be characterized as having a density of greater than about0.960 g/cm³.

In the embodiments illustrated in FIG. 3, polymerizing monomers of thepurified feed stream 11 can yield polymerization product stream 121. Inan embodiment, the polymerization product stream 121 (e.g.,polymerization product stream 120 in FIG. 1) can generally comprisevarious solids, semi-solids, volatile and nonvolatile liquids, gases andcombinations thereof. Polymerizing monomers of the purified feed stream11 can yield the polymerization product stream 121 generally comprisingunreacted monomer (e.g., ethylene), optional unreacted comonomer,by-products (e.g., ethane, which can be by-product ethane formed fromethylene and hydrogen), and a polymerization product (e.g., polymer andoptionally, copolymer). As used herein, an “unreacted monomer,” forexample, ethylene, refers to a monomer that was introduced into apolymerization reactor during a polymerization reaction but was notincorporated into a polymer. As used herein, an “unreacted comonomer”refers to a comonomer that was introduced into a polymerization reactorduring a polymerization reaction but was not incorporated into apolymer. The solids and/or liquids of the polymerization product stream121 can comprise a polymer product (e.g., a polyethylene polymer), oftenreferred to at this stage of the PEP process as “polymer fluff.” Thegases of the polymerization product stream 121 can comprise unreacted,gaseous reactant monomers or optional comonomers (e.g., unreactedethylene monomers, unreacted comonomers), gaseous waste products,gaseous contaminants, or combinations thereof.

In an embodiment, the polymerization product stream 121 can comprisehydrogen, nitrogen, methane, ethylene, ethane, propylene, propane,butane, 1-butene, isobutane, pentane, hexane, 1-hexene and heavierhydrocarbons. In an embodiment, ethylene can be present in a range offrom about 0.1% to about 15%, alternatively, from about 1.5% to about5%, alternatively, about 2% to about 4% by total weight of thepolymerization product stream. Ethane can be present in a range of fromabout 0.001% to about 4%, alternatively, from about 0.2% to about 0.5%by total weight of the polymerization product stream. Isobutane can bepresent in a range from about 80% to about 98%, alternatively, fromabout 92% to about 96%, alternatively, about 95% by total weight of thepolymerization product stream.

In an embodiment, the PEP process 2000 can generally comprise the step2300 of separating the polymerization product stream into a polymerstream and a gas stream. In one or more of the embodiments disclosedherein, separating the polymerization product into a polymer stream anda gas stream can generally comprise removing gases from liquids and/orsolids (e.g., the polymer fluff) by any suitable process.

In embodiments as illustrated by FIG. 1, separating the polymerizationproduct into a polymer stream and a gas stream can comprise routing thepolymerization product stream 120 to a separator (e.g., flash chamber200). In some embodiments, the polymerization product stream 120 cancomprise at least a portion of the polymerization product stream 121emitted from the second reactor 106. In other embodiments, thepolymerization product stream 120 can comprise at least a portion of themid-polymerization reactor stream 15 emitted from the first reactor 104.In yet other embodiments, the polymerization product stream 120 cancomprise at least a portion of the polymerization product stream 121 andat least a portion of the mid-polymerization reactor stream 15.

In one or more of the embodiments disclosed herein, a separator such asflash chamber 200 can be configured to separate a stream (e.g.,polymerization product stream 120 comprising polyethylene) into gases,liquids, solids, or combinations thereof.

In an embodiment, the separator for separating the polymerizationproduct stream into a polymer stream and a gas stream can comprise avapor-liquid separator. As will be appreciated by one of skill in theart, and with the help of this disclosure, the solids of thepolymerization product stream (e.g., polymer fluff) are slurried in theliquids of the polymerization product stream, and a vapor-liquidseparator would generally separate the solids and the liquid in a singleslurry phase from the gases of the polymerization product stream.Nonlimiting examples of separators suitable for use in the presentdisclosure a fixed-bed adsorption column, a flash tank, a filter, amembrane, a reactor, an absorbent, an adsorbent, a molecular sieve, orcombinations thereof.

In an embodiment, the separator comprises a flash tank (e.g., flashchamber 200). Without wishing to be limited by theory, such a flash tankcan comprise a vessel configured to vaporize and/or remove low vaporpressure components from a high temperature and/or high pressure fluid.The separator for separating the polymerization product into a polymerstream and a gas stream can be configured such that an incoming streamcan be separated into a liquid stream (e.g., a condensate stream) and agas (e.g., vapor) stream. The liquid stream can comprise a reactionproduct (e.g., polyethylene, often referred to as “polymer fluff”). Theliquid stream can be a bottoms stream. The gas or vapor stream cancomprise volatile solvents, gaseous, unreacted monomers and/or optionalcomonomers, waste gases (secondary reaction products, such ascontaminants and the like), or combinations thereof. The gas stream canbe an overhead stream.

The separator for separating the polymerization product into a polymerstream and a gas stream can be configured such that the polymerizationproduct stream is flashed by heat, pressure reduction, or both such thatan enthalpy of the polymerization product stream is increased. This canbe accomplished via a heater, a flashline heater, various otheroperations commonly known in the art, or combinations thereof. Forexample, a flash line heater comprising a double pipe can exchange heatby hot water or steam. Such a flashline heater can increase thetemperature of the stream while reducing its pressure.

In one or more embodiments, separating the polymerization product streaminto a polymer stream and a gas stream can comprise distilling,vaporizing, flashing, filtering, membrane screening, centrifuging,absorbing, adsorbing, or combinations thereof, the polymerizationproduct. In the embodiments illustrated in FIG. 1, separating thepolymerization product stream into a polymer stream and a gas streamyields a gas stream 210 and a polymer stream 220 (e.g., polyethylenepolymer, copolymer).

In an embodiment, the gas stream 210 can comprise unreacted monomer(e.g., unreacted ethylene monomer), optional unreacted comonomer, andvarious gases. Gas stream 210 can comprise the non-solid components ofpolymerization product stream 120 in a vapor phase. In an embodiment,the gas stream 210 can comprise hydrogen, nitrogen, methane, ethylene,ethane, propylene, propane, butane, isobutane, pentane, hexane,1-hexene, heavier hydrocarbons, or combinations thereof. In anembodiment, the gas stream 210 can further comprise trace amounts ofoxygen. In an embodiment, ethylene can be present in a range of fromabout 0.1% to about 15%, alternatively, from about 1.5% to about 5%,alternatively, about 2% to about 4% by total weight of the gas stream.Ethane can be present in a range of from about 0.001% to about 4%,alternatively, from about 0.2% to about 0.5% by total weight of the gasstream. Isobutane can be present in a range from about 80% to about 98%,alternatively, from about 92% to about 96%, alternatively, about 95% bytotal weight of the gas stream.

In some embodiments, the mid-polymerization reactor stream 15 can beprocessed in a similar manner to the polymerization product stream 121,wherein the mid-polymerization reactor stream 15 can be separated into amid-polymerization polymer stream and a mid-polymerization gas stream.In such embodiments, the mid-polymerization polymer stream can becommunicated to the second reactor 106; processed in a similar manner tothe polymer stream 220, as will be described in more detail laterherein; communicated to the purge column 400, such as for example viathe polymer stream 220; or combinations thereof. In such embodiments,the mid-polymerization gas stream can be processed in a similar mannerto the gas stream 210, as will be described in more detail later herein,and/or communicated to the heavy distillation column 300, such as forexample via the gas stream 210.

In an embodiment, the PEP process 2000 can generally comprise the step2400 of processing the gas stream in one or more distillation columns.In an embodiment, processing the gas stream 210 can comprise separatingat least one gaseous component from the gas stream. While the step ofprocessing the gas stream will be discussed in detail in the context oftwo distillation columns used for such processing of the gas stream, itshould be understood that any suitable number of distillation columnscan be used for processing the gas stream, such as for example one, two,three, four, five, or more distillation columns.

In an embodiment, separating at least one gaseous component from the gasstream can comprise distilling a gas stream (e.g., gas stream 210) inone step so as to allow at least one gaseous component to separate fromother gaseous components according to temperature(s) of boiling. In suchan embodiment, separating at least one gaseous component from the gasstream can comprise distilling a gas stream into a light hydrocarbonstream comprising ethylene, ethane, optionally hydrogen, or combinationsthereof. In such an embodiment, separating at least one gaseouscomponent from the gas stream can comprise collecting hexane, hexene,optionally isobutane, or combinations thereof in a distillation bottomsstream. In an additional and/or alternative embodiment, separating atleast one gaseous component from the gas stream can comprise collectingisobutane from a side stream and/or a distillation bottoms stream of adistillation column.

In the embodiment of the PEP system 1000 shown in FIG. 1, distillationcolumns 300 and 350 can be configured to separate at least one gaseouscomponent from a gas stream (e.g., gas stream 210). Processing the gasstream 210 in one or more distillation columns can yield severalhydrocarbon fractions. The gas stream 210 can be communicated to theheavy distillation column 300. Gas stream 210 can be distilled in theheavy distillation column 300 to form intermediate hydrocarbon stream330 which can be communicated to the light distillation column 350.Non-distilled components in the heavy distillation column 300 can emitfrom the heavy distillation column 300 in heavy distillation bottomsstream 310. Heavy distillation side stream 320 can optionally emit fromthe heavy distillation column 300.

Intermediate hydrocarbon stream 330 can be characterized as comprising,alternatively, comprising substantially, alternatively, consistingessentially of, alternatively, consisting of, C₄ and lighterhydrocarbons (e.g., butane, isobutane, propane, ethane, or methane) andany light gases (e.g., nitrogen). For example, C₄ and lighterhydrocarbons and gases can be present in the intermediate hydrocarbonstream 330 in an amount of from about 80% to about 100% by total weightof the intermediate hydrocarbon stream, alternatively from about 90% toabout 99.999999%, alternatively from about 99% to about 99.9999%,alternatively, C₅ and heavier hydrocarbons can be present in theintermediate hydrocarbon stream 330 in an amount from about 0% to about20% by total weight of the intermediate hydrocarbon stream,alternatively from about 10% to about 0.000001%, alternatively fromabout 1.0% to about 0.0001%. Also, for example, at least 90% by weightof the C₄ and lighter hydrocarbons and gases of the gas stream 210 canbe present in the intermediate hydrocarbon stream 330, alternatively, atleast 98%, alternatively, at least 99%.

In an embodiment, heavy distillation bottoms stream 310 can becharacterized as comprising C₆ and heavy components, wherein the heavycomponents can comprise alkanes, that is, alkanes larger than hexane(e.g., heptane and/or other large alkanes). In an embodiment,hydrocarbons other than C₆ and heavy alkanes can be present in the heavydistillation bottoms stream 310 in an amount less than about 15%,alternatively, less than about 10%, alternatively, less than about 5% bytotal weight of the heavy distillation bottoms stream 310. In anembodiment, the heavy distillation bottoms stream 310 can be directed toadditional processing steps or methods, or alternatively they can bedisposed of, as appropriate. In an embodiment, heavy distillationbottoms stream 310 can be incinerated.

In an embodiment, heavy distillation side stream 320 can becharacterized as comprising hexene. For example, hexene can be presentin heavy distillation side stream 320 in an amount of from about 20% toabout 98% by total weight of the heavy distillation side stream 320,alternatively from about 40% to about 95%, alternatively from about 50%to about 95%.

In an embodiment, the heavy distillation side stream 320 can berecycled. In an embodiment, recycling the heavy distillation side stream320 can comprise routing, for example, via a suitable pump orcompressor, the heavy distillation side stream 320 back to and/orintroducing the heavy distillation side stream 320 into one or morecomponents of the PEP system 1000, for example, into slurry loop reactorsystem 100 for reuse in a polymerization reaction. Recycling the heavydistillation side stream 320 can provide an efficient and/orcost-effective means of supplying hexene for operation of thepolymerization reaction process. In an embodiment, at least a portion ofthe hexene of the heavy distillation side stream 320 can be employed inthe polymerization reaction as, for example, a comonomer in thereaction. In an alternative embodiment, at least a portion of the heavydistillation side stream 320 can be routed to storage for subsequent usein a polymerization reaction or employed in any other suitable process.As will be appreciated by one of skill in the art, and with the help ofthis disclosure, at least a portion of the hexene can be recycled backto the reactor when the reactor is undergoing a polymerization reactioninvolving hexene as a comonomer. Further, as will be appreciated by oneof skill in the art, and with the help of this disclosure, at least aportion of the hexene can be stored when the reactor is undergoing apolymerization reaction in the absence of hexene.

In some embodiments, at least a portion of the heavy distillationbottoms stream 310 and/or heavy distillation side stream 320 can bereturned to the heavy distillation column 300. For example, at least aportion of the heavy distillation bottoms stream 310 and/or heavydistillation side stream 320 can be routed via a reboiler to the heavydistillation column 300 for additional processing.

In an embodiment, heavy distillation column 300 can be provided with oneor more inlets and at least two outlets. The heavy distillation column300 can be operated at a suitable temperature and pressure, for exampleas can be suitable to achieve separation of the components of the gasstream 210. For example, the heavy distillation column 300 can beoperated at a temperature in a range of from about 15° C. to about 233°C., alternatively, from about 20° C. to about 200° C., alternatively,from about 20° C. to about 180° C., and/or a pressure in a range of fromabout 14.7 psi to about 527.9 psi, alternatively, from about 15.7 psi toabout 348 psi, alternatively, from about 85 psi to about 290 psi. Theheavy distillation column 300 can be configured and/or sized to providefor separation of a suitable volume of gases (e.g., a flash gas stream).As will be appreciated by one of skill in the art viewing thisdisclosure, the gas stream 210 can remain and/or reside within heavydistillation column 300 for any suitable amount of time, for example anamount of time as can be necessary to provide sufficient separation ofthe components within the heavy distillation column 300.

In an embodiment, the gas stream 210 can be introduced into the heavydistillation column 300 without a compressive step, that is, withoutcompression of the gas stream 210 after it is emitted from the flashchamber 200 and before it is introduced into the heavy distillationcolumn 300. In another embodiment, the gas stream 210 can be introducedinto the heavy distillation column 300 at substantially the samepressure as the outlet pressure of flash chamber 200 (e.g., a pressureof from about 14.7 psia to about 527.9 psia, alternatively, from about15.7 psia to about 348 psia, alternatively, from about 85 psia to about290 psia at the outlet of the flash chamber 200). In still anotherembodiment, the gas stream 210 can be introduced into the heavydistillation column 300 without a significant compressive step. In anembodiment, gas stream 210 can be introduced into heavy distillationcolumn 300 at a pressure in a range of from about 25 psi less than thepressure at which the gas stream 210 was emitted from the flash chamber200 to about 25 psi greater than the pressure at which the gas stream210 was emitted from the flash chamber 200, alternatively, from about 15psi less than the pressure at which the gas stream 210 was emitted fromthe flash chamber 200 to about 15 psi greater than the pressure at whichthe gas stream 210 was emitted from the flash chamber 200,alternatively, from about 5 psi less than the pressure at which the gasstream 210 was emitted from the flash chamber 200 to about 5 psi greaterthan the pressure at which the gas stream 210 was emitted from the flashchamber 200. In an embodiment, the gas stream 210 can be introduced intothe heavy distillation column 300 at a pressure in a range of from about14.7 psia to about 527.8 psia, alternatively, from about 15.7 psia toabout 348 psia, from about 85 psia to about 290 psia.

In an embodiment, the heavy distillation column 300 can be configuredand/or operated such that each of the intermediate hydrocarbon stream330, the heavy distillation bottoms stream 310, and an optional heavydistillation side stream 320 can comprise a desired portion, part, orsubset of components of the gas stream 210. For example, as will beappreciated by one of skill in the art and with the help of thisdisclosure, the location of a particular stream outlet, the operatingparameters of the heavy distillation column 300, the composition of thegas stream 210, or combinations thereof can be manipulated such that agiven stream can comprise a particular one or more components of the gasstream 210.

In the embodiment of the PEP system 1000 shown in FIG. 1, theintermediate hydrocarbon stream 330 can be separated in the lightdistillation column 350 to form light hydrocarbon stream 380, lightdistillation bottoms stream 360, and optionally, light distillation sidestream 370. At least one gaseous component can be emitted from the lightdistillation column 350 in light hydrocarbon stream 380, and the othergaseous components can be emitted from the light distillation column 350in light distillation bottoms stream 360.

In an embodiment, light hydrocarbon stream 380 can be characterized ascomprising ethylene. For example, ethylene can be present in lighthydrocarbon stream 380 in an amount from about 50% to about 99% by totalweight of the light hydrocarbon stream 380, alternatively from about 60%to about 98%, alternatively, from about 70% to about 95%.

In an embodiment, the light hydrocarbon stream 380 can further compriseother light gases (e.g., ethane, methane, carbon dioxide, nitrogen,hydrogen, or combinations thereof). In some embodiments, the lighthydrocarbon stream 380 can comprise ethylene and ethane.

In an embodiment, light distillation bottoms stream 360 can becharacterized as comprising propane, butane, isobutane, pentane, hexane,heavier saturated hydrocarbons, or combinations thereof. In anembodiment, the light distillation bottoms stream 360 can be free ofolefins, alternatively, substantially free of olefins, alternatively,essentially free of olefins, alternatively, consisting essentially of orconsisting of non-olefins. For example, olefins can be present in lightdistillation bottoms stream 360 in an amount of less than about 1.0% bytotal weight of the light distillation bottoms stream 360,alternatively, less than about 0.5%, alternatively, less than about0.1%. In an embodiment, the light distillation bottoms stream 360 cancomprise olefin-free isobutane 365.

In an embodiment, light distillation side stream 370 can becharacterized as comprising isobutane. In an embodiment, lightdistillation side stream 370 comprising, alternatively, consisting of oressentially consisting of, isobutane can be emitted from the lightdistillation column 350. The isobutane of light distillation bottomsstream 360 can comprise a different grade of isobutane than theisobutane of light distillation side stream 370. For example, lightdistillation bottoms stream 360 can comprise isobutane that issubstantially free of olefins, and light distillation side stream 370can comprise a recycle isobutane which can include olefins.

In an embodiment, at least a portion of the light distillation sidestream 370 and/or light distillation bottoms stream 360 can be recycled.In some embodiments, recycling at least a portion of the lightdistillation side stream 370 and/or light distillation bottoms stream360 can comprise routing, for example, via a suitable pump orcompressor, at least a portion of the light distillation side stream 370and/or light distillation bottoms stream 360 back to and/or introducingat least a portion of the light distillation side stream 370 and/orlight distillation bottoms stream 360 into one or more components of thePEP system 1000, for example, into slurry loop reactor system 100 forreuse in a polymerization reaction. In an embodiment, at least a portionof the light distillation side stream 370 and/or light distillationbottoms stream 360 can be combined with various other components(catalysts, cocatalysts, etc.) to form a catalyst slurry that can beintroduced into one or more of reactors 104, 106. Without wishing to belimited by theory, because at least a portion of light distillationbottoms stream 360 can be free of olefins and can comprise isobutane,the light distillation bottoms stream 360 can be mixed with catalyticcomponents (e.g., catalysts, cocatalysts, etc.) without the risk ofunintended polymerization reactions (e.g., polymerization prior tointroduction into the one or more reactors). As such, at least a portionof light distillation bottoms stream 360 can serve as a source ofolefin-free isobutane for a polymerization reaction. Recycling at leasta portion of the light distillation side stream 370 and/or lightdistillation bottoms stream 360 can provide an efficient and/orcost-effective means of supplying isobutane for operation of thepolymerization reaction process. In an alternative embodiment, at leasta portion of the light distillation side stream 370 and/or lightdistillation bottoms stream 360 can be routed to storage for subsequentuse in a polymerization reaction or employed in any other suitableprocess.

In some embodiments, at least a portion of the light distillation sidestream 370 and/or light distillation bottoms stream 360 can be recycledto a TSA unit, for example via a sweeping gas stream. The lightdistillation bottoms stream 360 comprising olefin-free isobutane 365 canbe recycled 366 to the TSA unit 500, for example via the sweeping gasstream 510, as shown in FIG. 1.

In other embodiments, at least a portion of the light distillation sidestream 370 and/or light distillation bottoms stream 360 can be routed tostorage for subsequent use in any suitable process.

In yet other embodiments, at least a portion of the light distillationside stream 370 and/or light distillation bottoms stream 360 can bereturned to the light distillation column 350. For example, at least aportion of the light distillation side stream 370 and/or lightdistillation bottoms stream 360 can be routed via a reboiler to thelight distillation column 350 for additional processing.

The light distillation column 350 can be configured and/or sized providefor separation of a suitable volume of gases. For example, the lightdistillation column 350 can be operated at a temperature in a range offrom about 50° C. to about 20° C., alternatively, from about 40° C. toabout 10° C., alternatively, from about 30° C. to about 5° C., and apressure in a range of from about 14.7 psia to about 529.7 psia,alternatively, from about 15.7 psia to about 348 psia, alternatively,from about 85 psia to about 290 psia. The light distillation column 350can be configured and/or sized to provide for separation of a suitablevolume of intermediate hydrocarbon stream 330. As will be appreciated byone of skill in the art, the intermediate hydrocarbon stream 330 canremain and/or reside within light distillation column 350 for anysuitable amount of time as can be necessary to provide sufficientseparation of the components of intermediate hydrocarbon stream 330. Inan embodiment, light distillation column 350 can be provided with atleast two outlets.

In an embodiment, the light distillation column 350 can be configuredand/or operated such that each of light hydrocarbon stream 380 and thelight distillation bottoms stream 360 can comprise a desired portion,part, or subset of components of the intermediate hydrocarbon stream330. For example, as will be appreciated by one of skill in the art withthe aid of this disclosure, the location of a particular stream inlet oroutlet, the operating parameters of the light distillation column 350,the composition of the intermediate hydrocarbon stream 330, orcombinations thereof can be manipulated such that a given stream cancomprise a particular one or more components of the intermediatehydrocarbon stream 330.

In an embodiment, the PEP process 2000 can generally comprise the step2500 of purging the polymer stream to produce a purged polymer streamand a spent purge gas stream. In the embodiment of the PEP system 1000shown in FIG. 1, a primary solids feed to the purge column 400 comprisestypically the polymer stream 220. Generally, the polymer stream 220comprises a solids discharge (e.g., polyolefin fluff, such as forexample polyethylene fluff) that exits the flash chamber 200. A purposeof the purge column 400 is to remove residual hydrocarbon from polymerstream 220 and to provide a substantially-clean polymer fluff (e.g.,polymer 425) with relatively small amounts of entrained volatile organiccontent. The polymer 425 (e.g., polymer fluff) can be transported orconveyed to an extrusion/loadout system for conversion to pellets and/orfor distribution and sale as polyolefin pellet resin.

Referring to the embodiment of FIG. 1, the polymer stream 220 cancomprise a polymer (e.g., polyethylene), unreacted monomer (e.g.,ethylene, 1-hexene) and various gases (e.g., ethane, isobutane,hydrogen, methane, propane, butane, pentane, hexane, propylene).Processing (e.g., purging) the polymer stream 220 can yield the purgedpolymer stream 420 and the spent purge gas stream 430 generallycomprising a purge gas (e.g., nitrogen), unreacted monomer (e.g.,ethylene, 1-hexene), and various gases (e.g., ethane, isobutane,hydrogen, nitrogen, methane, propylene, propane, butane, pentane,hexane, heavier hydrocarbons).

Referring to the embodiment of FIG. 1, a purge gas 410 (e.g., an inertgas, nitrogen) can be circulated through purge column 400 to removeresidual hydrocarbons via a spent purge gas stream 430. The spent purgegas stream 430 can be communicated to a separation unit, such as forexample a TSA unit 500, for ethylene recovery.

In an embodiment, purge column 400 can be a cylindrical vessel having arelatively tall vertical section, a cover or head at the top, slopedsides or conical shape at the bottom with an opening for polymer fluffdischarge. The polymer fluff to be degassed of volatile hydrocarbons canenter the vessel at the top, while the purge gas, typically nitrogen,can be introduced to the vessel in the sloped bottom sides. Flow can becountercurrent between the purge gas and polymer fluff in the vessel. Incertain embodiments, a hydrocarbon rich purge gas (e.g., spent purge gas430) can leave the purge column through an opening at the top, while adegassed fluff (e.g., purged polymer stream 420) can leave at the bottomof the purge column.

Degassing effectiveness in the purge column can be predicated on themaintenance of an uniform plug flow of the polymer fluff and purge gasin the purge column, thereby ensuring good contact between the two. Adiameter (D) of the purge column can typically range from about 5 toabout 6 feet, but a length (L) of the purge column can be chosen toachieve a residence time (e.g., from about 30 to about 180 minutes)sufficient for degassing the polymer fluff. In some embodiments, L/Dratios can range from about 4 to about 8; however, L/D ratios can beoutside this range. In an embodiment, internal features can be employedin the purge column, such as a distributor plate for introducing purgegas (e.g., nitrogen), an inverted cone for facilitating plug flow of thepolymer (e.g., to reduce bridging or channeling of the polymer fluff),and the like.

In one or more of the embodiments disclosed herein, processing thepurged polymer stream 420 (e.g., polymer 425) comprises any suitableprocess or series of processes configured to produce a polymer productas can be suitable for commercial or industrial usage, storage,transportation, further processing, or combinations thereof.

In an embodiment, processing the purged polymer stream 420 can compriserouting the purged polymer stream 420 to a polymer processor. Thepolymer processor can be configured for the performance of a suitableprocessing means (e.g., to form various articles), nonlimiting examplesof which include cooling, injection molding, melting, pelletizing, filmblowing, cast film, blow molding, extrusion molding, rotational molding,thermoforming, cast molding, fiber spinning, and the like, orcombinations thereof. Various additives and modifiers can be added tothe polymer to provide better processing during manufacturing and fordesired properties in the end product. Nonlimiting examples of suchadditives can include surface modifiers such as slip agents, antiblocks,tackifiers; antioxidants such as primary and secondary antioxidants;pigments; processing aids such as waxes/oils and fluoroelastomers;and/or special additives such as fire retardants, antistats, scavengers,absorbers, odor enhancers, and degradation agents.

The polymer can include other suitable additives. Such additives can beused singularly or in combination and can be included in the polymerbefore, during or after preparation of the polymer as described herein.Such additives can be added via known techniques, for example during anextrusion or compounding step such as during pelletization or subsequentprocessing into an end use article.

In an embodiment, the polymer processor can be configured to form asuitable polymer product. Nonlimiting examples of suitable polymerproducts as can result from processing the purged polymer stream includefilms, powders, pellets, resins, liquids, or any other suitable form aswill be appreciated by those of skill in the art. Such a suitable outputcan be for use in, for example, one or more of various consumer orindustrial products. For example, the polymer product can be utilized inany one or more of various articles, including, but not limited to,bottles, drums, toys, containers, household containers, utensils, filmproducts, tanks, fuel tanks, pipes, membranes, geomembranes, and liners.In an embodiment, the polymer processor is configured to form pelletsfor transportation to a consumer product manufacturer.

In an embodiment, the PEP process 2000 can generally comprise the step2600 of contacting the spent purge gas stream with a temperature swingadsorber contactor (TSAC) to yield a loaded TSAC and a non-adsorbed gasstream. In an embodiment, at least one gaseous component (e.g.,ethylene) can be separated from the spent purge gas stream 430 duringstep 2600.

In one or more one or more of the embodiments disclosed herein,separating at least one gaseous component from a gas stream (e.g., thespent purge gas stream 430) generally comprises any suitable method ofselectively separating at least a first chemical component or compoundfrom a stream comprising the first chemical component or compound andone or more other chemical components, compounds, or the like. Invarious embodiments, the gaseous component separated from the gas streamcan comprise one or more hydrocarbons. Non-limiting examples of suchhydrocarbons include alkanes (e.g., ethane, butane, isobutane, hexane,and the like, or combinations thereof) and alkenes or olefin monomers(e.g., ethylene) or optional comonomers. In an embodiment, the gaseouscomponent separated from the gas stream can comprise an unreactedhydrocarbon monomer, e.g., ethylene. Optionally, the gaseous componentseparated from the gas stream can comprise an unreacted hydrocarboncomonomer. In an embodiment, the gaseous component separated from thegas stream can comprise an unreacted hydrocarbon monomer (e.g.,ethylene, alone or in combination with other hydrocarbons, such as,ethane, isobutane, hexane, or combinations thereof), or optionally,hydrocarbon comonomer alone or in combination with other hydrocarbons,such as, isobutane, hexane, or combinations thereof. In an embodiment,the gaseous component separated from the gas stream can compriseethylene, alone or in combination with isobutane. In an embodiment,capturing isobutane can result in a savings of the cost of the capturedisobutane and reduce the presence of isobutane in flare emissions.Nonlimiting examples of suitable separating means include distilling,vaporizing, flashing, filtering, membrane screening, absorbing,adsorbing, molecular weight exclusion, size exclusion, polarity-basedseparation, or combinations thereof.

In an embodiment, at least one gaseous component (e.g., ethylene) can beseparated from the spent purge gas stream 430 by temperature swingadsorption. Recovering ethylene from the spent purge gas stream 430 cangenerally comprise contacting the spent purge gas stream 430 with theTSAC in a TSA unit 500 to yield a loaded TSAC generally comprisingTSAC-adsorbed ethylene, and a non-adsorbed gas stream 520 generallycomprising nitrogen, ethane, isobutane.

For purposes of the disclosure herein, the term “loaded” when used todescribe or when referring to a TSAC (e.g., “loaded TSAC”), is intendedto be nonlimiting, and is intended to denote (e.g., mean, signify,indicate, represent, etc.) that the TSAC has an amount of a hydrocarbon(e.g., ethylene, ethane, etc.) adsorbed therein (e.g., adsorbedethylene, adsorbed ethane, etc.). Further, for purposes of thedisclosure herein, the term “loaded” when used to describe a TSAC (e.g.,“loaded TSAC”), is intended to include any amount of an adsorbedhydrocarbon, such as for example an amount of adsorbed hydrocarbon ofequal to or greater than about 10%, alternatively equal to or greaterthan about 15%, alternatively equal to or greater than about 20%,alternatively equal to or greater than about 25%, alternatively equal toor greater than about 30%, alternatively equal to or greater than about40%, alternatively equal to or greater than about 50%, alternativelyequal to or greater than about 60%, alternatively equal to or greaterthan about 70%, alternatively equal to or greater than about 80%,alternatively equal to or greater than about 90%, alternatively equal toabout 100%, based on the adsorption capacity of the TSAC at a giventemperature (e.g., first temperature). Without wishing to be limited bytheory, the adsorption capacity of the TSAC at a given temperature(e.g., first temperature) can be defined as the ratio of the maximumamount of hydrocarbon that can be adsorbed by the TSAC to the amount ofhydrocarbon adsorber present in the TSAC, and it can be expressed in gadsorbed hydrocarbon/g hydrocarbon adsorber. As will be appreciated byone of skill in the art and with the help of this disclosure, the term“adsorbed hydrocarbon” refers to a hydrocarbon (e.g., ethylene, ethane,etc.) that is adsorbed or associated with an adsorbent (e.g., adsorbentassociated hydrocarbon) in a reversible fashion, wherein the adsorbentis a hydrocarbon adsorber of the type disclosed herein.

In an embodiment, the loaded TSAC can be a partially loaded TSAC,wherein the partially loaded TSAC can comprise an amount of adsorbedhydrocarbon of from about 10% to about 50%, alternatively from about 15%to about 45%, or alternatively from about 20% to about 40%, based on theadsorption capacity of the TSAC at the first temperature.

In an embodiment, the loaded TSAC can be a substantially loaded TSAC,wherein the substantially loaded TSAC can comprise an amount of adsorbedhydrocarbon of from about 50% to about 99%, alternatively from about 55%to about 95%, or alternatively from about 60% to about 90%, based on theadsorption capacity of the TSAC at the first temperature.

In an embodiment, the loaded TSAC can be a completely or fully loadedTSAC (alternatively referred to as a saturated TSAC), wherein thecompletely loaded TSAC can comprise an amount of adsorbed hydrocarbon ofabout 100%, alternatively about 99.5%, or alternatively about 99%, basedon the adsorption capacity of the TSAC at the first temperature.

As will be appreciated by one of skill in the art, and with the help ofthis disclosure, the TSAC can undergo an adsorption step (e.g., the TSACcan adsorb) to yield a loaded TSAC, such as for example a substantiallyloaded TSAC or a completely loaded TSAC, and subsequently the loadedTSAC (e.g., substantially loaded TSAC, completely loaded TSAC) canundergo a regeneration step (e.g., the TSAC can regenerate) to yield aTSAC or a partially loaded TSAC. The TSAC can be characterized by afirst adsorption capacity at the first temperature, and by a secondadsorption capacity at a second temperature, wherein the firsttemperature is greater than the second temperature, and wherein thefirst adsorption capacity is greater than the second adsorptioncapacity, thereby enabling an adsorption step at the first temperatureand a desorption/regeneration step at the second temperature.

In an embodiment, separating at least one gaseous component from thespent purge gas stream can comprise contacting the spent purge gasstream with an adsorbent (e.g., TSAC, as disclosed herein), for example,so as to allow the gaseous component to be adsorbed by the adsorbent. Insuch an embodiment, separating at least one gaseous component from thespent purge gas stream comprises selectively adsorbing the at least onegaseous component from a spent purge gas stream. In such an embodiment,adsorbing the at least one gaseous component from the spent purge gasstream generally comprises contacting the spent purge gas stream with asuitable adsorbent, allowing the at least one component to be adsorbedby the adsorbent, and, optionally, removing a waste stream comprisingunadsorbed gases (e.g., non-adsorbed gas stream 520). In an additionalembodiment, separating at least one gaseous component from the spentpurge gas stream can further comprise liberating the adsorbed gaseouscomponent from the adsorbent (e.g., recovered adsorbed gas stream 530).

In an embodiment, the TSAC comprises a plurality of hollow tubes and ahydrocarbon adsorber, wherein the hollow tube comprises a hollow tubeouter surface, wherein at least a portion of the hollow tube outersurface is in contact with the hydrocarbon adsorber. In an embodiment, aphysical structure of the TSAC can be arranged to provide for asufficient contact surface area between the hydrocarbon adsorber and thehollow tube outer surface, which in turn can provide for rapid heatexchange, thereby enabling rapid cycles of a temperature swingadsorption process, as will be described in more detail later herein.

In an embodiment, the hollow tubes comprise very small diameter tubes(e.g., microtubes). In an embodiment, the hollow tubes can becharacterized by an inner diameter of from about 0.1 mm to about 5 mm,alternatively from about 0.2 mm to about 2 mm, or alternatively fromabout 0.25 mm to about 1.5 mm. As will be appreciated by one of skill inthe art and with the help of this disclosure, a cross-section of thehollow tubes has a circular geometry; however, other geometries of thecross-section of the hollow tubes can be possible, such as for exampleoval, square, hexagonal, etc.

In an embodiment, a heating transfer fluid (e.g., a cooling fluid, aheating fluid) can pass through at least a portion of the hollow tube(e.g., through at least a portion of an inner hollow part of the tubes).

In an embodiment, the hollow tubes can be characterized by a hollow tubethickness of from about 0.1 mm to about 1 mm, alternatively from about0.15 mm to about 0.8 mm, or alternatively from about 0.2 mm to about 0.5mm. Generally, a tube thickness can be calculated by subtracting aninner tube diameter from an outer tube diameter and dividing suchdifference by 2.

In an embodiment, the hollow tubes can be characterized by a hollow tubelength. The hollow tube length can vary depending on the overall desiredlength of the TSAC. In some embodiments, the hollow tubes, which cancarry cooling and/or heating fluid, can be aligned substantiallyparallel to the flow of a feed gas (e.g., spent purge gas 430, sweepinggas 510, etc.). In other embodiments, the hollow tubes can be alignedsubstantially perpendicular, or at any other suitable angle, to thedirection of flow of feed gas. In yet other embodiments, the hollowtubes can be changing direction throughout a length of the TSAC, such asfor example in a net-like structure, mesh structure, weaved structure,braided structure, etc.

In an embodiment, the hollow tubes can be characterized by a hollow tubelength of from about 1 mm to about 500 mm, alternatively from about 10mm to about 250 mm, or alternatively from about 50 mm to about 150 mm.In an embodiment, the hollow tubes can be characterized by any suitablehollow tube length. As will be appreciated by one of skill in the art,and with the help of this disclosure, the hollow tube length can be anysuitable length that can enable the rapid cycles of a temperature swingadsorption process, as will be described in more detail later herein.

The hollow tubes can be manufactured from any suitable material so longas their integrity is capable of withstanding the gaseous environmentsas well as pressure and temperature swings which they will be subjectedto when used in a TSA process.

In an embodiment, the hollow tubes comprise a thermally conductivematerial. As will be appreciated by one of skill in the art, and withthe help of this disclosure, during a TSA process, the hollow tubes haveto be capable of effectively transmitting heat (e.g., a thermal wave)between an inner hollow tube surface and an outer hollow tube surface.

In an embodiment, the hollow tubes can comprise a metal, aluminum,nickel, an alloy, stainless steel, thermally conductive polymers,polymeric materials, latexes, polyvinylidene chloride latex, carbon,glass, ceramics, or combinations thereof.

In an embodiment, the TSAC comprises a hydrocarbon adsorber. In anembodiment, the hydrocarbon adsorber comprises a substance, materialand/or compound capable of facilitating adsorption and desorption of ahydrocarbon (e.g., ethylene, ethane, etc.) from a hydrocarbon mixture(e.g., spent purge gas stream) by way of a temperature swing adsorptionprocess. For example, the hydrocarbon adsorber can comprise a substance,material and/or compound capable of adsorbing hydrocarbons, preferablyin a selective manner. Generally, the hydrocarbon adsorber can comprisesany material capable of selectively adsorbing one or more hydrocarboncomponents of a gas mixture (e.g., a spent purge gas stream). In anembodiment, the hydrocarbon adsorber can selectively adsorb one or morehydrocarbons at a first temperature, and can selectively desorb (e.g.,regenerate) one or more hydrocarbons at a second temperature, whereinthe first temperature is greater than the second temperature.

Nonlimiting examples of hydrocarbon adsorbers suitable for use in thepresent disclosure include a molecular sieve, a 4 A molecular sieve, azeolite, metal-organic frameworks (MOFs), carbon, molecular sievecarbon, zeolitic imidazolate frameworks (ZIFs), or combinations thereof.

In an embodiment, the hydrocarbon adsorber comprises a zeolite. The term“zeolite” generally refers to a particular group of hydrated,crystalline metal aluminosilicates. Zeolites typically are orderedporous crystalline aluminosilicates having a structure withpores/cavities and channels interconnected by channels. The pores andchannels throughout the crystalline material generally can be of a sizeto allow selective separation of hydrocarbons. Generally, zeolitesexhibit a network of SiO₄ and AlO₄ tetrahedra in which aluminum andsilicon atoms are crosslinked in a three-dimensional framework bysharing oxygen atoms. In the framework, the ratio of oxygen atoms to thetotal of aluminum and silicon atoms can be equal to 2. The frameworkexhibits a negative electrovalence that typically is balanced by theinclusion of cations within a crystal structure of the aluminosilicates,such as for example metals, alkali metals, alkaline earth metals, orhydrogen.

Nonlimiting examples of zeolites suitable for use as hydrocarbonadsorbers in the present disclosure include a cationic zeolite, analuminosilicate, an alkali metal aluminosilicate, a sodiumaluminosilicate, an X zeolite, a NaX zeolite, a 13X zeolite, an Azeolite, a NaA zeolite, KA zeolite, NaCaA zeolite, or combinationsthereof.

In an embodiment, the hydrocarbon adsorber comprises a porous material.Such porous material can comprise open pores that are interconnected toallow hydrocarbons to enter the hydrocarbon adsorber and be adsorbed insuch pores. In some embodiments, the size of the pores can be such thatonly certain hydrocarbons will be able to enter the pores and beadsorbed within the pores. In an embodiment, the pores of thehydrocarbon adsorber can have a size of from about 2 Angstroms to about10 Angstroms, alternatively from about 2 Angstroms to about 6 Angstroms,alternatively from about 3 Angstroms to about 5 Angstroms, oralternatively about 4 Angstroms.

In some embodiments, a size of the pores within the zeolite is about 4Angstroms, thereby rendering such zeolite (also known as a 4 A molecularsieve or a 4 A zeolite) suitable for selectively separating certainhydrocarbons, such as for example separating ethylene from ethane.

In an embodiment, the TSAC further comprises a support, wherein thehydrocarbon adsorber contacts at least a portion of the support, isdistributed throughout the support, or combinations thereof, and wherebythe hydrocarbon adsorber is structurally supported by the support. In anembodiment, the hydrocarbon adsorber can be disposed about the support.In an embodiment, the hydrocarbon adsorber can be associated with thesupport.

The support can be comprised of any suitable material and/or of anysuitable construction and can be porous or non-porous. In someembodiments, the support can be comprised entirely of a hydrocarbonadsorber. In other embodiments, the support can be comprised entirely ofa (relatively) non-adsorbent material towards hydrocarbons.

In an embodiment, the support can contact a hydrocarbon adsorber,wherein the hydrocarbon adsorber comprises a layer on the support;wherein the hydrocarbon adsorber can be embedded within the structure ofthe support, or the like, or combinations thereof.

In an embodiment, the support comprises a film, a foil, a mesh, a fibercloth, a woven fiber mesh, a woven wire mesh, a metallic woven wiremesh, a polymeric membrane, a surface treated material, a surfacetreated metal foil, a woven fiber cloth, or combinations thereof.

In an embodiment, the support comprises a thermally conductive polymer(e.g., a porous thermally conductive polymer, a foamed thermallyconductive polymer, etc.). As will be appreciated by one of skill in theart, and with the help of this disclosure, during a TSA process, theTSACs have to be capable of effectively transmitting heat (e.g., athermal wave) across the TSAC. Further, as will be appreciated by one ofskill in the art, and with the help of this disclosure, when the supportis a porous thermally conductive polymer and/or a foamed thermallyconductive polymer, the hydrocarbon adsorber can be present in the poresof such porous and/or foamed support material, whereby the hydrocarbonadsorber is structurally supported by the support.

Nonlimiting examples of supports suitable for use in the presentdisclosure include cellulose acetate, polyvinylpyrrolidone, orcombinations thereof.

In some embodiments, the support can be a woven fiber cloth or fibermesh wherein at least a fraction of fibers are comprised of ahydrocarbon adsorber and wherein the remaining fraction is comprised ofa non-adsorbent material. In some embodiments, the hydrocarbon adsorbercan also be comprised of zeolite crystals embedded within the support.

In an embodiment, the thickness of a support layer can be any effectivethickness. For purposes of the disclosure herein the effective thicknessof a support layer represents any thickness capable of providing atleast a minimum integrity needed under TSA process conditions for anintended overall structure of the TSAC, whether it is a spiral woundstructure, a layered non-spiral structure, etc.

In an embodiment, the support comprises a non-adsorbent material towardshydrocarbons. In such embodiment, the support can be treated by anysuitable treating technique to incorporate at least an effective amountof a hydrocarbon adsorber on/within the support material. Nonlimitingexamples of treating techniques for applying a hydrocarbon adsorber tothe support suitable for use in the present disclosure include washcoating techniques, in situ crystallization methods that deposit ahydrocarbon adsorber directly onto the support from a synthesissolution, doctor-blading, spraying, spray-coating, electrodeposition,dry-wet spinning, or the like.

In an embodiment, the support can be coated with a hydrocarbon adsorberby wash-coating. A typical wash-coating process involves a slurrypreparation (e.g., molecular sieve particles, a suitable binder, andoptionally a viscosifying agent), slurry application by washing ordipping, drying, and/or sintering. Once a wet coating is formed, suchcoating has to be dried and sintered at relatively high temperatures(e.g., from about 300° C. to about 600° C.) to establish binding amongcoating components and adhesion between coating and a surface of thesupport.

In an embodiment, the support comprises a porous material (e.g., afoamed material) and the hydrocarbon adsorber can be applied in a mannerin which particles of hydrocarbon adsorber fill at least a portion ofthe pores of a porous structure of the support. For example, a slurrycontaining hydrocarbon adsorber crystals can be soaked into, orpressured through, a porous layered support material, then such layeredsupport can be dried and/or calcined.

As will be appreciated by one of skill in the art and with the help ofthis disclosure, a coated support can typically have two major opposingsupport surfaces, and one or both of these surfaces can be coated withthe hydrocarbon adsorber. In an embodiment, a thickness of the support,plus applied hydrocarbon adsorber and/or any other materials (e.g., adesiccant, a catalyst, etc.) can range from about 0.010 mm to about 2mm, alternatively from about 0.10 mm to about 1 mm, or alternativelyfrom about 0.15 mm to about 0.3 mm.

In an embodiment, the TSAC can be assembled by using any suitablemethodology compatible with materials and methods disclosed herein. Insome embodiments, the hollow tubes and the support (e.g., a foil typesupport, a layered support, etc.) can be in good thermal contact witheach other. In such embodiments, the hollow tubes and the support can bebrazed, welded, or soldered together in at least some locations to bothincrease heat transfer rates and strengthen the structure.

In an embodiment, the TSAC comprises a TSAC structure wherein aplurality of hollow tubes contacting a hydrocarbon adsorber can behoused, and wherein a geometry of the TSAC structure is defined by thesupport. In such embodiment, the TSAC structure can have a cylindricalgeometry.

In some embodiments, the hollow tubes can extend past the hydrocarbonadsorber, and the ends of the hollow tubes can be sealed away from thehydrocarbon adsorber (e.g., in a sealing end cap), such that a heatexchange fluid that passes through the hollow tubes does not contact thehydrocarbon adsorber. Nonlimiting examples of materials suitable for usein the sealing end caps include solder, brazing material, and/orpolymeric materials such as epoxy. As will be appreciated by one ofskill in the art, and with the help of this disclosure, the sealing endcap should be of suitable physical integrity to be able to withstandprolonged use at operating conditions.

In an embodiment, the TSAC can comprise a gas mixture inlet and a gasmixture outlet. In some embodiments, open flow channels can be providedthrough the hydrocarbon adsorber for the flow of gaseous mixtures (e.g.,a spent purge gas, a sweeping gas, etc.), wherein the open flow channelscan be continuous between the gas mixture inlet and the gas mixtureoutlet of the TSAC. In some embodiments, the gas mixture inlet and thegas mixture outlet can be located on a body of the TSAC between thesealing end caps. As will be appreciated by one of skill in the art, andwith the help of this disclosure, the heat exchange fluid that passesthrough the hollow tubes should generally be kept isolated from a feedgas mixture and product gases flowing to, through, and from the openflow channels. This can be accomplished by any suitable means, such asby having a suitable sealing device (e.g., sealing end cap) at each endof the TSAC.

In some embodiments, the open flow channels and hollow tubes can beoriented substantially parallel to each other in the TSAC. Inlet andoutlet ends of each of the open flow channels and the hollow tubes canbe oriented in the TSAC on substantially opposite ends, such that feedgases and heat exchange fluids pass substantially parallel to oneanother from one end of the TSAC to the other. In other embodiments, theopen flow channels and hollow tubes can be oriented substantiallynon-parallel to each other in the TSAC.

In an embodiment, a TSAC structure can comprise spacers. Generally,spacers can provide a fixed distance between layers or sheets of astructure (e.g., a TSAC structure). The spacers can be either integralto the TSAC of they can be a non-integral independent material. Whenspacers are integral to the TSAC (e.g., support), then the spacers couldbe formed during manufacturing of the TSAC, such as dimples orcorrugations (e.g., within the support) of a predetermined size toprovide a desired flow channel volume of the open flow channels. Whenspacers are not integral to the TSAC, then the spacers can be comprisedof any suitable material that can be relatively inactive in the TSAC andthat should not typically decompose under TSA process conditions.Nonlimiting examples of spacer materials suitable for use in the presentdisclosure include particles, such as glass microspheres, wires ofsuitable size, and the like, or combinations thereof.

In an embodiment, a layer of hydrocarbon adsorber can be applied to asheet of support, as previously described herein, before placement ofthe hollow tubes and/or after placement of the hollow tubes in contactwith the hydrocarbon adsorber and/or the support.

In some embodiments, the TSAC can comprise a spiral wound structure,wherein the hollow tubes can be supported by at least one layer of thehydrocarbon adsorber and, in most cases, can be sandwiched between twosurfaces of hydrocarbon adsorber. A spiral wound structure of a TSAC canbe constructed by a prefabrication technique wherein a plurality ofhollow tubes can be placed on a substantially flat sheet of hydrocarbonadsorber. In an embodiment, a spiral wound structure can be assembled bywounding structure components around a mandrel of suitable compositionand dimensions relative to a desired final spiral wound structure of theTSAC. In an embodiment, a suitable banding device (e.g., bands,fasteners, clasps, ties, clips, pins, etc.) can be used to secure thespiral wound structure in a desired geometry (e.g., cylindrical), and toprevent it from unraveling/telescoping. Brazing material or adhesivescan optionally be used to bond the hollow tubes to the hydrocarbonadsorber, thereby adding rigidity and strength to the overall structure.

In other embodiments, the TSAC can comprise a stacked layered sheetstructure. The stacked layered sheet structure can be assembled by firstpreparing a single layer substructure, then folding it back and forth onitself multiple times until a final desired stacked layered sheetstructure can be achieved.

In yet other embodiments, the TSAC can comprise a plurality of hollowtubes in contact with an inner surface of a support layer, wherein anouter surface of the same support layer can be in contact with thehydrocarbon adsorber. The TSAC can comprise a plurality of supportlayers. In such embodiments, the TSAC can further comprise spacers,wherein the spacers can define open flow channels. A distance betweenthe support layers can be defined by the outer diameter of the hollowtubes.

In still yet other embodiments, the TSAC can comprise a support in acorrugated form, wherein the support comprises folds or furrows. In suchembodiments, the hollow tubes can occupy at least a portion of thefolds. Both sides of the corrugated support can comprise the hydrocarbonadsorber, except for surfaces within the folds, which can be occupied bythe hollow tubes. Open flow channels can be formed between two opposingcorrugated support layers.

In still yet other embodiments, the TSAC can comprise a support, whereinan inner surface of the support contacts the hollow tubes and can becoated with the hydrocarbon adsorber, and wherein an outer surface ofthe support is not coated with the hydrocarbon adsorber. In suchembodiments, the inner surface of the support can be coated with thehydrocarbon adsorber before and/or after contacting the inner surface ofthe support with the hollow tubes. In some embodiments, an outer surfaceof the hollow tubes can be coated with the hydrocarbon adsorber. Thesupport layers contacting the hollow tubes and the hydrocarbon adsorberscan be stacked in any suitable manner to form the TSAC. For example, theouter surfaces of the support from two adjacent layers can contact eachother, and the inner surfaces comprising the hollow tubes can contacteach other, wherein the spacing between the hollow tubes can create openflow channels. As another example, the outer surface of the support fromone layer can contact the inner surface of a support comprising thehollow tubes from an adjacent layer, wherein the spacing between thehollow tubes can create open flow channels. Such configurations canalternate within a TSAC. The TSAC can further comprise spacers tocontrol the position and size of open flow channels. Otherconfigurations of TSACs are described in more detail in U.S. PatentPublication No. 20120222554 A1, which is incorporated by referenceherein in its entirety.

In an embodiment, the TSAC comprises a plurality of hollow fibercontactors. In an embodiment, the hollow fiber contactor comprises thesupport in contact with the outer surface of the hollow tubes, whereinthe hollow fiber contactor has an outer cylindrical geometry owing to acylindrical geometry of the support. In some embodiments, the hollowfiber contactors can be bundled together, thereby creating open flowspaces between adjacent hollow fiber contactors.

In an embodiment, the hollow fiber contactor comprises a hollow tube,and a hydrocarbon adsorber dispersed throughout and supported within asupport (e.g., porous polymer) as shown in FIG. 4A. In an embodiment, aheat exchange fluid can pass through the hollow tube, while a sweepinggas can flow across the support/hydrocarbon adsorber, as shown in FIG.4B.

In an embodiment, hollow fiber contactors can be assembled by using anonsolvent phase inversion technique commonly referred to as “dry-wetspinning.” In such embodiment, polymer solutions (e.g., polymer supportsolutions) comprising hydrocarbon adsorber particles (e.g., zeoliteparticles, molecular sieve particles, etc.), solvents, nonsolvents,additives for tunning phase equilibria, can be extruded through a dieinto a nonsolvent quench bath, thereby forming a hollow fiber. In anembodiment, the hollow fiber comprises a continuous polymer networkwherein hydrocarbon adsorber particles are entrapped within such polymernetwork. In an embodiment, the polymer solution comprisesN-methyl-2-pyrrolidone (NMP), cellulose acetate, andpolyvinylpyrrolidone, wherein polyvinylpyrrolidone can act as a poreformer. In an embodiment, the hydrocarbon adsorber comprises a 4 Amolecular sieve. In an embodiment, the hollow tube of the hollow fibercontactor can be formed by coating an inner surface of the hollow fiberswith a polymer, such as for example a latex form of polyvinylidenechloride. Hollow fiber contactors, which can also be referred to ashollow fiber adsorbents, are described in more detail in Ind. Eng. Chem.Res. 2009, 48, pp 7314-7324, which is incorporated by reference hereinin its entirety.

TSACs rely on temperature swing adsorption (TSA) as a process forselectively separating at least one gaseous component from a gas mixture(e.g., hydrocarbon mixture, spent purge gas stream, etc.). TSA processesrely on the fact that under pressure gases tend to be adsorbed within apore structure of a microporous adsorbent material (e.g., hydrocarbonadsorber) or within a free volume of a polymeric material. Withoutwishing to be limited by theory, gas adsorption within an adsorption bedis generally an exothermic process, thereby causing a rise intemperature during such adsorption. An elevated temperature can causethe gas to be desorbed, which is generally undesirable during anadsorption step. One way to circumvent this problem is by cooling theadsorption bed during the adsorption step. By cyclically swinging thetemperature of adsorbent beds, TSA processes can be used to separategases in a mixture when used with an adsorbent that is selective for oneor more of the components of a gas mixture.

In an embodiment, a TSAC can be repeatedly cycled through at least twosteps: an adsorption step and a regeneration/desorption step (e.g.,thermally assisted desorption step). Regeneration of the TSACs can beachieved by increasing the temperature of the TSAC to a temperatureeffective in desorbing at least a portion of the gas or gases that wereadsorbed by the TSAC during the adsorption step. The TSAC can then becooled so that another adsorption step can be performed. In someembodiments, the regeneration step can be assisted with use of a partialpressure purge displacement, or even a pressure swing, such as forexample running a sweeping gas which can be pressurized across a TSAC.For purposes of the disclosure herein, any combination of processes thatinvolves a thermally assisted desorption step, whether it is used inconjunction with a pressure change or not, will be referred to as TSA orTSA process.

In an embodiment, the TSA process can be conducted with rapid cycles, inwhich case it can be referred to as a rapid cycle temperature swingadsorption (RCTSA) process. For purposes of the disclosure herein, theterms TSA and RCTSA can be used interchangeably.

In an embodiment, the TSAC can be characterized by a cycle time of fromabout 10 seconds to about 1 hour, alternatively from about 15 seconds toabout 30 minutes, or alternatively from about 30 seconds to about 10minutes. For purposes of the disclosure herein, the cycle time of theTSAC can be defined as the time between the start of two successiveadsorption steps, e.g., a time frame necessary to complete an adsorptionstep and a regeneration step that are consecutive.

In an embodiment, the relatively small dimensions of the hollow tubesand of the TSACs can effectively utilize/maximize surface area for heatexchange while reducing/minimizing the mass and/or total sensibleheating requirements of the TSAC. In an embodiment, the TSAC can becharacterized by a relatively low mass per surface area, given theporosity of the hydrocarbon adsorber and the relatively small dimensionsof the hollow tubes. Generally, the TSAC is characterized by relativelyshort heat transfer distances, wherein a heat transfer can occur betweena heat exchange fluid and the hydrocarbon adsorber and/or support,thereby enabling relatively rapid temperature swings (e.g., RCTSA) whenused for thermal swing adsorption. The TSAC can provide a system forgeneration of relatively sharp thermal waves in both the hydrocarbonadsorber and/or support, as well as in the hollow tubes (e.g., heattransfer fluid channels). In some embodiments, such sharp thermal wavescan enable both selective sequential desorption of multiple adsorbedspecies (e.g., different hydrocarbons) and enable efficient heatrecovery.

In an embodiment, during the adsorption step, a cooling fluid can passthrough (e.g., be flowed through) at least a portion of the hollow tubesprior to and/or during contacting the TSAC with a gaseous mixture (e.g.,spent purge gas stream). Nonlimiting examples of cooling fluids suitablefor use in the present disclosure include water, tap water, processwater, an aqueous solution, or combinations thereof. The presence of thecooling fluid in the hollow tubes can advantageously increase the totalheat capacity of the TSAC to limit a temperature rise during theadsorption step to an effectively small range.

In an embodiment, during the regeneration step, a heating fluid can passthrough (e.g., be flowed through) at least a portion of the hollow tubesduring heating the loaded TSAC. Nonlimiting examples of heating fluidssuitable for use in the present disclosure include warm water, hotwater, steam, or combinations thereof.

In some embodiments, the heat exchange fluid (e.g., cooling fluid,heating fluid) can be recovered subsequent to passing through at least aportion of the hollow tubes, to yield a recovered heat exchange fluid.As will be appreciated by one of skill in the art, and with the help ofthis disclosure, a temperature of the recovered heat exchange fluidcould need to be adjusted (e.g., cool the cooling fluid, heat theheating fluid, etc.) prior to reusing the recovered heat exchange fluidin a TSAC.

In an embodiment, the adsorption step can occur at a first temperatureand the regeneration step can occur at a second temperature. Forpurposes of the disclosure herein, the first temperature of theadsorption step is considered to be about the same temperature as thetemperature of the cooling fluid, and about the same as the temperatureof the TSAC during the adsorption step, given the efficient heattransfer that occurs within the TSAC. Further, for purposes of thedisclosure herein, the second temperature of the regeneration step isconsidered to be about the same temperature as the temperature of theheating fluid, and about the same as the temperature of the TSAC duringthe regeneration step (e.g., loaded TSAC), given the efficient heattransfer that occurs within the TSAC. As will be appreciated by one ofskill in the art, and with the help of this disclosure, this efficientheat transfer is what enables the short cycle times (e.g., RCTSA) aspreviously described herein. Further, as will be appreciated by one ofskill in the art, and with the help of this disclosure, a fluid velocityof the heat exchange fluid within the hollow tubes can be adjusted suchthat the heat exchange fluid does not substantially change itstemperature while passing through the hollow tubes. In an embodiment,the heat exchange fluid can be characterized by an initial temperature(e.g., a temperature at an entrance point into a hollow tube) and afinal temperature (e.g., a temperature at an exit point from a hollowtube). In some embodiments, a difference between an initial temperatureand a final temperature, wherein the smaller value is subtracted fromthe larger value, can be less than about 10° C., alternatively less thanabout 9° C., alternatively less than about 8° C., alternatively lessthan about 7° C., alternatively less than about 6° C., alternativelyless than about 5° C., alternatively less than about 4° C.,alternatively less than about 3° C., alternatively less than about 2°C., or alternatively less than about 1° C.

In an embodiment, the first temperature can be in the range of fromabout 10° C. to about 100° C., alternatively from about 25° C. to about75° C., or alternatively from about 30° C. to about 60° C.

In an embodiment, the second temperature can be in the range of fromabout 20° C. to about 200° C., alternatively from about 40° C. to about150° C., or alternatively from about 50° C. to about 100° C.

In an embodiment, the second temperature can be greater than the firsttemperature by equal to or greater than about 10° C., alternatively bygreater than about 25° C., or alternatively by greater than about 50° C.

In an embodiment, the use of very small inner diameter hollow tubes tocontain the heat exchange fluid, in conjunction with relatively highcrush and burst strength capabilities of the hollow tubes andhydrocarbon adsorber and/or support, can enable using of the TSAC withrelatively high differential pressures between a feed fluid (e.g., gasmixture, spent purge gas, sweeping gas, etc.) and the heat exchangefluid. In some embodiments, such relatively high differential pressurescan be at least about 100 psi, alternatively at least about 200 psi,alternatively at least about 300 psi, alternatively at least about 400psi, alternatively at least about 500 psi, alternatively from about 100psi to about 2,000 psi, alternatively from about 300 psi to about 1,500psi, alternatively from about 400 psi to about 1,000 psi, alternativelyfrom about 500 psi to about 750 psi, or alternatively from about 100 psito about 200 psi.

In an embodiment, the spent purge gas stream can be contacted with aTSAC to yield a loaded TSAC and a non-adsorbed gas stream during anadsorption step. In such embodiment, the adsorption step can occur at afirst temperature. In an embodiment, the spent purge gas stream can becharacterized by a pressure of from about 100 kPa to about 200 kPa,alternatively from about 120 kPa to about 180 kPa, or alternatively 140kPa to about 160 kPa.

Referring to the embodiment of FIG. 1, the spent purge gas stream 430that is emitted from purge column 400 can have a temperature that ishigher than the first temperature. In such embodiment, the spent purgegas stream can be optionally cooled to about the first temperature priorto contacting at least a portion of the spent purge gas stream with theTSAC. For example, the spent purge gas stream can be sent to a heatexchanger for cooling prior to contacting with the TSAC.

In an embodiment, the TSAC can be cooled and/or maintained to about thefirst temperature during the adsorption step by passing a cooling fluidthrough at least a portion of the hollow tubes of the TSAC.

In an embodiment, the spent purge gas stream can comprise a lowconcentration of ethylene, e.g., the spent purge gas stream comprises adilute ethylene stream. In an embodiment, the ethylene of the spentpurge gas stream can be characterized by a partial pressure of fromabout 1 kPa to about 20 kPa, alternatively from about 2 kPa to about 15kPa, or alternatively 8 kPa to about 12 kPa. In an embodiment, at leasta portion of the ethylene present in the spent purge gas stream can beadsorbed by the TSAC at the first temperature to yield TSAC-adsorbedethylene. In an embodiment, the loaded TSAC comprises TSAC-adsorbedethylene.

In an embodiment, the spent purge gas stream can comprise a lowconcentration of ethane, e.g., the spent purge gas stream comprises adilute ethane stream. In an embodiment, the ethylene of the spent purgegas stream can be characterized by a partial pressure of from about 0.1kPa to about 10 kPa, alternatively from about 0.5 kPa to about 8 kPa, oralternatively 1 kPa to about 5 kPa. In an embodiment, a portion of theethane present in the spent purge gas stream can be adsorbed by the TSACat the first temperature to yield TSAC-adsorbed ethane. In anembodiment, the loaded TSAC comprises TSAC-adsorbed ethane.

In some embodiments, the spent purge gas stream can be characterized bya ratio of a partial pressure for ethylene to a partial pressure forethane of from about 1 to about 25, alternatively from about 1.5 toabout 15, or alternatively from about 2 to about 10.

In an embodiment, the TSAC can selectively adsorb ethylene versusethane. Without wishing to be limited by theory, an adsorptionselectivity (S) of a first compound (e.g., a first hydrocarbon, such asfor example ethylene) versus a second compound (e.g., a secondhydrocarbon, such as for example ethane) for a given temperature can becalculated based on the following formula S=(x₁/x₂)(y₂/y₁), wherein x₁and x₂ are mole fractions in the adsorbed phase of the first compoundand of the second compound, respectively, wherein y₁ and y₂ are molefractions in the bulk or gas phase of the first compound and of thesecond compound, respectively, and wherein all mole fractions are givenfor the temperature at which the selectivity is being reported.

In an embodiment, the TSAC can be characterized by an adsorptionselectivity of ethylene versus ethane at the first temperature of equalto or greater than about 5, alternatively greater than about 7, oralternatively greater than about 10.

In an embodiment, the non-adsorbed gas stream 520 can further comprisesmall amounts of ethylene (e.g., ethylene that was not adsorbed by theTSAC). As will be appreciated by one of skill in the art, and with thehelp of this disclosure, nitrogen and isobutane will not be adsorbed bythe hydrocarbon adsorber of the TSAC, as such hydrocarbon adsorber isspecifically chosen for selectively adsorbing ethylene. A small amountof ethane can be adsorbed by the hydrocarbon adsorber of the TSAC,however, as indicated by the adsorption selectivity of ethylene versusethane of the TSAC, the amount of ethane adsorbed by the hydrocarbonadsorber is much lower than the amount of ethylene adsorbed by thehydrocarbon adsorber.

In an embodiment, the PEP process 2000 can generally comprise the step2700 of heating the loaded TSAC to yield a regenerated TSAC. Heating theloaded TSAC can yield a regenerated TSAC and desorbed ethylene.

In an embodiment, at least a portion of the loaded TSAC can be heated toa second temperature to yield a regenerated TSAC, desorbed ethylene anddesorbed ethane, wherein the desorbed ethylene comprises at least aportion of the TSAC-adsorbed ethylene, and wherein the desorbed ethanecomprises at least a portion of the TSAC-adsorbed ethane. As will beappreciated by one of skill in the art, and with the help of thisdisclosure, depending on the value of the second temperature, it isunlikely that the entire amount of TSAC-adsorbed hydrocarbons (e.g.,TSAC-adsorbed ethylene, TSAC-adsorbed ethane) will be desorbed duringthe regeneration step. Depending on the affinity of the hydrocarbons forthe hydrocarbon adsorber, after a first TSAC cycle, some amount ofhydrocarbons (e.g., ethylene, ethane) can remain adsorbed by the TSACthroughout further adsorption/regeneration cycles. As will beappreciated by one of skill in the art, and with the help of thisdisclosure, the TSACs can be calcined (e.g., heated to hightemperatures, for example greater than about 300° C.) to remove residualadsorbed hydrocarbons and then returned into the PEP process.

In an embodiment, a molar ratio of desorbed ethylene to TSAC-adsorbedethylene can be from about 0.01 to about 1, alternatively from about 0.1to about 0.9, or alternatively from about 0.2 to about 0.8.

In an embodiment, a molar ratio of desorbed ethane to TSAC-adsorbedethane can be from about 0 to about 1, alternatively from about 0.3 toabout 0.9, or alternatively from about 0.4 to about 0.8.

In an embodiment, the loaded TSAC can be heated to the secondtemperature during the regeneration step by passing a heating fluidthrough at least a portion of the hollow tubes of the loaded TSAC.

In an embodiment, the PEP process 2000 can generally comprise the step2800 of contacting the regenerated TSAC with a sweeping gas stream toyield a recovered adsorbed gas stream. Contacting the regenerated TSACwith a sweeping gas stream 510 (e.g., olefin-free isobutane) can yield arecovered adsorbed gas stream 530, wherein the sweeping gas sweeps awaythe desorbed ethylene. At least a portion of the recovered adsorbed gasstream 530 comprising ethylene can be pressurized and re-introduced 536(e.g., as shown in FIG. 1) into a PEP process (e.g., into the slurryloop reactor system 100), for example via the reagents stream 110.

In an embodiment, the step of contacting the TSAC with a sweeping gasstream can occur prior to, concurrent with, or subsequent to the step ofheating the loaded TSAC to yield a regenerated TSAC. In an embodiment,the step of contacting the TSAC with a sweeping gas stream and the stepof heating the loaded TSAC to yield a regenerated TSAC can occurconcurrently within the same TSA unit.

In an embodiment, a sweeping gas stream 510 can be communicated to theTSA unit 500 during a regeneration step to aid in the recovery of theadsorbed hydrocarbons. Without wishing to be limited by theory, thesweeping gas (e.g., olefin-free isobutane) generally flows through theopen flow channels of the TSAC and carries away any desorbedhydrocarbons (e.g., desorbed ethylene, desorbed ethane) that itencounters in its path.

In an embodiment, the sweeping gas stream 510 can be heated to about thesecond temperature prior to being contacted with the TSAC.

In an embodiment, the recovered adsorbed gas stream 530 comprisessweeping gas, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane. As will be appreciated by one of skill in theart, and with the help of this disclosure, the amount of ethane presentin the recovered adsorbed gas stream is very low and its presence is dueto a low amount of ethane being adsorbed by the TSAC. For purposes ofthe disclosure herein, the recovered adsorbed gas stream primarilycontains a sweeping gas and ethylene. In an embodiment, the recoveredadsorbed gas stream 530 comprises isobutane and ethylene 535. In anembodiment, a molar ratio of ethylene to ethane in the recoveredadsorbed gas stream 530 can be equal to or greater than about 5,alternatively greater than about 7, or alternatively greater than about10.

In an embodiment, the recovered adsorbed gas stream 530 can beoptionally cooled in a heat exchanger and collected in a recycle diluentsurge tank for feed to a reactor (e.g., reactor 104, reactor 106). In anembodiment, the isobutane and ethylene 535 can be pressurized (e.g., viaone or more compressors) to yield a reintroduction stream 536 (e.g., asshown in FIG. 1) that can be recycled to the reagents stream 110. Insome embodiments, the reintroduction stream 536 can be communicated tothe purifier 102. As will be appreciated by one of skill in the art, andwith the help of this disclosure, the amount of ethylene and isobutanepresent in the reintroduction stream 536 is dependent on a variety offactors, such as for example ethylene recovery rate, olefin-freeisobutane flow rate (e.g., sweeping gas stream flow rate), ethyleneconcentration in the spent purge gas stream, etc.

In an embodiment, ethylene can be present in the reintroduction stream536 in a range of from about 0.1 wt. % to about 50 wt. %, alternativelyfrom about 0.5 wt. % to about 25 wt. %, or alternatively from about 1wt. % to about 10 wt. %, by total weight of the reintroduction stream.In an embodiment, isobutane can be present in the reintroduction stream536 in a range of from about 50 wt. % to about 99.9 wt. %, alternativelyfrom about 75 wt. % to about 99.5 wt. %, or alternatively from about 90wt. % to about 99 wt. %, by total weight of the reintroduction stream.

In an embodiment, a TSA unit comprises at least one TSAC disposedtherein. In some embodiments, a TSA unit comprises a plurality of TSACsdisposed therein.

In an embodiment, the TSA unit 500 as shown in FIG. 1 comprises at leasttwo TSA units working in parallel. For example, the adsorption step(e.g., contacting the spent purge gas stream with the TSAC) occurs in afirst temperature swing adsorption unit and the regeneration step (e.g.,heating of the loaded TSAC and contacting the regenerated TSAC with asweeping gas stream) occurs in a second temperature swing adsorptionunit, wherein the first temperature swing adsorption unit and the secondtemperature swing adsorption unit are operated in parallel.

In some embodiments, the TSA unit comprises a single TSA unit, whereinboth the adsorption step and the regeneration step occur in the same TSAunit. In such embodiments, the TSA unit can comprise moving beds (e.g.,moving TSAC beds) that can separate gases (e.g., ethylene from ethane)in a single TSA unit with subsequent steps. As will be appreciated byone of skill in the art, and with the help of this disclosure, movingbed technologies require solid sorbent/adsorbent with superior stabilityand rapid regeneration. Further, as will be appreciated by one of skillin the art, and with the help of this disclosure, moving bedtechnologies typically use steam for the regeneration step.

In an embodiment, the PEP process 2000 can generally comprise the step2900 of separating the non-adsorbed gas stream into a nitrogen streamand an isobutane and ethane stream. Referring to the embodiment of FIG.1, a non-adsorbed gas stream 520 can be communicated from the TSA unit500 to the INRU 600. Separating the non-adsorbed gas stream 520 into anitrogen stream 610 and an isobutane and ethane stream 620 can beaccomplished in the INRU 600. The nitrogen stream 610 can be recycled616 to the purge column 400, for example via the purge gas stream 410.The isobutane and ethane stream 620 can be recycled 626 to the heavydistillation column 300, for example via the gas stream 210, accordingto the embodiments of the PEP system 1000 in FIG. 1.

In an embodiment, INRU 600 can comprise a membrane recovery unit, apressure swing adsorption unit, a refrigeration unit, and the like. TheINRU 600 can separate the non-adsorbed gas stream into the nitrogenstream 610 and the isobutane and ethane stream 620. At least a portionof the nitrogen 615 can be recycled 616 to the purge column 400, forexample via the purge gas stream 410. Moreover, fresh nitrogen can beadded to a nitrogen circuit comprising the purge gas stream 410 toaccount for nitrogen losses in the purge column 400, in the TSA unit 500and/or in the INRU 600.

In an embodiment, the isobutane and ethane 625 can comprise isobutane,ethane, hexane and other heavy hydrocarbons. In some embodiments, atleast a portion of the isobutane and ethane 625 can be recycled 626 tothe heavy distillation column 300, for example via the gas stream 210.In other embodiments, at least a portion of the isobutane and ethane 625can be optionally cooled in a heat exchanger and collected in a recyclediluent surge tank for feed to a reactor (e.g., reactor 104, reactor106).

The various embodiments shown in the Figures can be simplified and maynot illustrate common equipment such as heat exchangers, pumps, andcompressors; however, a skilled artisan would recognize the disclosedprocesses and systems may include such equipment commonly usedthroughout polymer manufacturing.

A skilled artisan will recognize that industrial and commercialpolyethylene manufacturing processes can necessitate one or more, oftenseveral, compressors or similar apparatuses. Such compressors are usedthroughout polyethylene manufacturing, for example to pressurizereactors 104, 106 during polymerization. Further, a skilled artisan willrecognize that a polyethylene manufacturing process includes one or moredeoxygenators and/or similar de-oxidizing apparatuses, for instance forpurifying solvents or reactants and/or for purging reactors of oxygen.Because the infrastructure and the support therefore, for example toprovide power and maintain the compressors and/or deoxygenators, alreadyexists within a commercial polyethylene manufacturing plant,reallocating a portion of these available resources for use in thedisclosed systems can necessitate little, if any, additional capitalexpenditure in order to incorporate the disclosed systems and orprocesses.

Further, because compressors, deoxygenators, and various othercomponents are already employed in various polyethylene processes andsystems, the opportunity for increased operation of such apparatuses canimprove the overall efficiency of polyethylene production systems andprocesses. For example, when a portion of a PEP process or system istaken off-line for maintenance and/or repair, other portions of thesystem (e.g., a compressor, a deoxygenator, a reactor, etc.) cancontinue to provide service according to the current processes.Operating and/or reallocating resources for operation of the disclosedPEP systems and/or processes can thereby increase the efficiency withwhich conventional systems are used.

In an embodiment, a process for component (e.g., hydrocarbon) separationin a polymer production system can comprise the steps of (a) separatinga polymerization product stream into a gas stream and a polymer stream,wherein the polymer stream comprises polyethylene, ethylene and ethane;(b) contacting at least a portion of the polymer stream with nitrogen toyield a purged polymer stream and a spent purge gas stream, wherein thepurged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises nitrogen, ethylene, and ethane, wherein a pressureof the spent purge gas stream is from about 100 kPa to about 150 kPa,wherein ethylene is characterized by a partial pressure of less thanabout 10 kPa, and wherein ethane is characterized by a partial pressureof less than about 5 kPa; (c) contacting at least a portion of the spentpurge gas stream with a TSAC comprising a 4 A zeolite and a plurality ofhollow tubes at about 20° C. to yield a loaded TSAC and a non-adsorbedgas stream, wherein at least a portion of the ethylene is adsorbed bythe TSAC to yield TSAC-adsorbed ethylene, wherein a portion of theethane is adsorbed by the TSAC to yield TSAC-adsorbed ethane, whereinthe loaded TSAC comprises TSAC-adsorbed ethylene and TSAC-adsorbedethane, and wherein the TSAC is characterized by an adsorptionselectivity of ethylene versus ethane at 20° C. of equal to or greaterthan about 5; (d) passing water at a temperature of about 50° C. throughat least a portion of the hollow tubes of the loaded TSAC to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, and wherein the desorbed ethane comprises at least a portionof the TSAC-adsorbed ethane; and (e) contacting at least a portion ofthe 4 A zeolite of the regenerated TSAC with olefin-free isobutane toyield a recovered adsorbed gas stream comprising isobutane, recoveredethylene and recovered ethane, wherein the recovered ethylene comprisesat least a portion of the desorbed ethylene, and wherein the recoveredethane comprises at least a portion of the desorbed ethane. In suchembodiment, a cooling fluid comprising water can pass through at least aportion of the hollow tubes prior to and/or during (c) contacting thespent purge gas stream with the TSAC.

In an embodiment, a process for hydrocarbon recovery can comprise thesteps of (a) providing a hydrocarbon stream comprising a firsthydrocarbon and a second hydrocarbon, wherein the hydrocarbon stream ischaracterized by a pressure of from about 100 kPa to about 200 kPa,wherein the first hydrocarbon is characterized by a partial pressure offrom about 1 kPa to about 20 kPa, and wherein the second hydrocarbon ischaracterized by a partial pressure of from about 0.1 kPa to about 10kPa; (b) contacting at least a portion of the hydrocarbon stream with aTSAC to yield a loaded TSAC and a non-adsorbed gas stream, wherein atleast a portion of the first hydrocarbon is adsorbed by the TSAC at afirst temperature to yield TSAC-adsorbed first hydrocarbon, wherein aportion of the second hydrocarbon is adsorbed by the TSAC at the firsttemperature to yield TSAC-adsorbed second hydrocarbon, wherein theloaded TSAC comprises TSAC-adsorbed first hydrocarbon and TSAC-adsorbedsecond hydrocarbon, and wherein the TSAC is characterized by anadsorption selectivity of first hydrocarbon versus second hydrocarbon atthe first temperature of equal to or greater than about 5; (c) heatingat least a portion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed first hydrocarbon and desorbed secondhydrocarbon, wherein the desorbed first hydrocarbon comprises at least aportion of the TSAC-adsorbed first hydrocarbon, wherein the desorbedsecond hydrocarbon comprises at least a portion of the TSAC-adsorbedsecond hydrocarbon, and wherein the second temperature is greater thanthe first temperature by equal to or greater than about 10° C.; and (d)contacting at least a portion of the regenerated TSAC with a sweepinggas stream to yield a recovered adsorbed gas stream, wherein therecovered adsorbed gas stream comprises a sweeping gas, recovered firsthydrocarbon and recovered second hydrocarbon, wherein the recoveredfirst hydrocarbon comprises at least a portion of the desorbed firsthydrocarbon, and wherein the recovered second hydrocarbon comprises atleast a portion of the desorbed second hydrocarbon. In such embodiment,the first hydrocarbon can comprise ethylene, the second hydrocarbon cancomprise ethane, and the sweeping gas can comprise olefin-freeisobutane.

In an embodiment, a TSAC system can comprise a TSA unit; wherein thetemperature swing adsorption unit comprises at least one TSAC disposedtherein; wherein the TSAC comprises a plurality of hollow tubes and ahydrocarbon adsorber, wherein the hollow tube comprises a hollow tubeouter surface, wherein at least a portion of the hollow tube outersurface is in contact with the hydrocarbon adsorber; wherein the TSACcomprises a support, wherein the hydrocarbon adsorber contacts at leasta portion of the support, is distributed throughout the support, orcombinations thereof; wherein the temperature swing adsorption unitadsorbs at a first temperature, wherein the hydrocarbon adsorber adsorbsa first amount of a first hydrocarbon characterized by a first partialpressure and a second amount of a second hydrocarbon characterized by asecond partial pressure to yield a loaded TSAC comprising aTSAC-adsorbed first hydrocarbon and a TSAC-adsorbed second hydrocarbon;wherein the hydrocarbon adsorber has an adsorption selectivity of thefirst hydrocarbon versus the second hydrocarbon at the first temperatureof equal to or greater than about 5; wherein the temperature swingadsorption unit regenerates at a second temperature, wherein the loadedTSAC is regenerated to yield a regenerated TSAC, a third amount of arecovered first hydrocarbon and a fourth amount of a recovered secondhydrocarbon; wherein the second temperature is greater than the firsttemperature by equal to or greater than about 10° C.; wherein a molarratio of the third amount to the first amount at the first partialpressure is from about 0.01 to about 1; and wherein a molar ratio of thefourth amount at the second partial pressure to the second amount isfrom about 0 to about 1. In such embodiment, the first hydrocarbon cancomprise ethylene, and the second hydrocarbon can comprise ethane.

In an embodiment, one or more of the disclosed systems (e.g., PEP system1000) and/or processes (e.g., PEP process 2000) can advantageouslydisplay improvements in one or more system and/or processcharacteristics when compared to otherwise similar systems and/orprocesses lacking a step of ethylene recovery in a TSA unit. In anembodiment, the TSA unit as disclosed herein can advantageously allowfor the recovery of a substantial portion of ethylene that wouldotherwise be lost due to conventional operation of such systems orprocesses, for example, by flaring. In an embodiment, one or more of thedisclosed systems can allow for the recovery of up to about 75%,alternatively, up to about 85%, alternatively, up to about 90%,alternatively, up to about 95% by total weight of ethylene from a spentpurge gas stream that would otherwise be lost. The recovery of such aportion of ethylene (e.g., unreacted ethylene monomers) can yield asignificant economic benefit, for example, by improving the efficiencyof usage of ethylene and decreasing capital inputs associated with theacquisition of ethylene.

In an embodiment, the TSA unit as disclosed herein can advantageouslydecrease the amount of ethane that is returned to a polymerizationreactor (such as reactors 104 and/or 106) via a recycle stream (e.g.,stream 536). By decreasing the amount of ethane contained in a stream toa polymerization reactor, the overall efficiency of the polyethyleneproduction can be improved (for example, by increasing the ethyleneconcentration without reaching a bubble point in the loop reactor). Forexample, decreasing the amount of ethane in a stream can improvepolymerization reactor efficiency, improve catalyst efficiency, reducepolymer fouling, reduce polymerization downtime, improve production ofbimodal polymer types, improve production of copolymers, or combinationsthereof.

In an embodiment, the TSA unit as disclosed herein can advantageouslyreduce a load on a compressor of the INRU due to a reduced gas streamthroughput through such compressor. In some embodiments where the INRUcomprises a pressure swing adsorption bed, such bed can advantageouslydisplay an increased capacity for isobutane adsorption, owing to thedecreased content of ethylene in the gas stream entering the INRU. Inother embodiments where the INRU comprises a membrane recovery unit,such membrane can advantageously display an increased throughput ofisobutane, owing to the decreased content of ethylene in the gas streamentering the INRU. Additional advantages of the systems and/or processesfor the production of a polyethylene polymer as disclosed herein can beapparent to one of skill in the art viewing this disclosure.

For the purpose of any U.S. national stage filing from this application,all publications and patents mentioned in this disclosure areincorporated herein by reference in their entireties, for the purpose ofdescribing and disclosing the constructs and methodologies described inthose publications, which might be used in connection with the methodsof this disclosure. Any publications and patents discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the inventors are not entitled to antedate such disclosure byvirtue of prior invention.

The present disclosure is further illustrated by the following examples,which are not to be construed in any way as imposing limitations uponthe scope thereof. On the contrary, it is to be clearly understood thatresort can be had to various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, canbe suggest to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

ADDITIONAL DISCLOSURE

The following enumerated embodiments are provided as non-limitingexamples.

A first embodiment which is a process for component separation in apolymer production system, comprising (a) separating a polymerizationproduct stream into a gas stream and a polymer stream, wherein thepolymer stream comprises polyethylene, ethylene and ethane; (b)contacting at least a portion of the polymer stream with a purge gas toyield a purged polymer stream and a spent purge gas stream, wherein thepurged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises purge gas, ethylene, and ethane; (c) contacting atleast a portion of the spent purge gas stream with a temperature swingadsorber contactor (TSAC) to yield a loaded TSAC and a non-adsorbed gasstream, wherein at least a portion of the ethylene is adsorbed by theTSAC at a first temperature to yield TSAC-adsorbed ethylene, wherein aportion of the ethane is adsorbed by the TSAC at the first temperatureto yield TSAC-adsorbed ethane, and wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane; (d) heating at least aportion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, and wherein the desorbed ethane comprises at least a portionof the TSAC-adsorbed ethane; and (e) contacting at least a portion ofthe regenerated TSAC with a sweeping gas stream to yield a recoveredadsorbed gas stream, wherein the recovered adsorbed gas stream comprisessweeping gas, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.

A second embodiment which is the process of the first embodiment whereinthe TSAC is characterized by an adsorption selectivity of ethyleneversus ethane at the first temperature of equal to or greater than about5.

A third embodiment which is the process of any of the first throughsecond embodiments wherein the second temperature is greater than thefirst temperature by equal to or greater than about 10° C.

A fourth embodiment which is the process of any of the first throughthird embodiments wherein the ethylene of the spent purge gas stream ischaracterized by a partial pressure of from about 1 kPa to about 20 kPa.

A fifth embodiment which is the process of any of the first throughfourth embodiments wherein the ethane of the spent purge gas stream ischaracterized by a partial pressure of from about 0.1 kPa to about 10kPa.

A sixth embodiment which is the process of any of the first throughfifth embodiments wherein a ratio of a partial pressure for ethylene toa partial pressure for ethane in the spent purge gas stream is fromabout 1 to about 25.

A seventh embodiment which is the process of any of the first throughsixth embodiments wherein the spent purge gas stream is characterized bya pressure of from about 100 kPa to about 200 kPa.

An eighth embodiment which is the process of any of the first throughseventh embodiments wherein the spent purge gas stream is further cooledto about the first temperature prior to (c) contacting at least aportion of the spent purge gas stream with the TSAC.

A ninth embodiment which is the process of any of the first througheighth embodiments wherein the first temperature is from about 10° C. toabout 100° C.

A tenth embodiment which is the process of any of the first throughninth embodiments wherein the second temperature is from about 20° C. toabout 200° C.

An eleventh embodiment which is the process of any of the first throughtenth embodiments wherein a molar ratio of desorbed ethylene toTSAC-adsorbed ethylene is from about 0.01 to about 1.

A twelfth embodiment which is the process of any of the first througheleventh embodiments, wherein a molar ratio of desorbed ethane toTSAC-adsorbed ethane is from about 0 to about 1.

A thirteenth embodiment which is the process of any of the first throughtwelfth embodiments wherein at least a portion of the recovered adsorbedgas stream is recycled as a reagent for the polymer production system,wherein the recovered adsorbed gas stream comprises isobutane andethylene.

A fourteenth embodiment which is the process of any of the first throughthirteenth embodiments wherein at least a portion of the gas stream isdistilled into a light distillation bottoms stream comprisingolefin-free isobutane, wherein at least a portion of the lightdistillation bottoms stream is used as the sweeping gas stream for (e)contacting at least a portion of the regenerated TSAC.

A fifteenth embodiment which is the process of any of the first throughfourteenth embodiments wherein at least a portion of the non-adsorbedgas stream is separated into a nitrogen stream and an isobutane andethane stream.

A sixteenth embodiment which is the process of the fifteenth embodimentwherein at least a portion of the nitrogen stream is used as the purgegas for (b) contacting the polymer stream.

A seventeenth embodiment which is the process of any of the fifteenththrough sixteenth embodiments wherein at least a portion of theisobutane and ethane stream is distilled into a light distillationbottoms stream comprising olefin-free isobutane.

An eighteenth embodiment which is the process of any of the firstthrough seventeenth embodiments wherein (c) contacting the spent purgegas stream occurs in a first temperature swing adsorption unit and (d)heating of the loaded TSAC and (e) contacting the regenerated TSACoccurs in a second temperature swing adsorption unit, wherein the firsttemperature swing adsorption unit and the second temperature swingadsorption unit are operated in parallel.

A nineteenth embodiment which is the process of any of the first througheighteenth embodiments wherein (d) heating the loaded TSAC and (e)contacting the regenerated TSAC occur concurrently within the sametemperature swing adsorption unit.

A twentieth embodiment which is the process of any of the first throughnineteenth embodiments wherein the TSAC comprises a plurality of hollowtubes and a hydrocarbon adsorber, wherein the hollow tube comprises ahollow tube outer surface, wherein at least a portion of the hollow tubeouter surface is in contact with the hydrocarbon adsorber.

A twenty-first embodiment which is the process of the twentiethembodiment wherein the hydrocarbon adsorber comprises a zeolite,metal-organic frameworks, carbon, molecular sieve carbon, zeoliticimidazolate frameworks, or combinations thereof.

A twenty-second embodiment which is the process of any of the twentieththrough twenty-first embodiments wherein the hydrocarbon adsorbercomprises a 4 A molecular sieve.

A twenty-third embodiment which is the process of the twenty-firstembodiment wherein the zeolite comprises a cationic zeolite, analuminosilicate, an alkali metal aluminosilicate, a sodiumaluminosilicate, an X zeolite, a NaX zeolite, a 13X zeolite, an Azeolite, a NaA zeolite, KA zeolite, NaCaA zeolite, or combinationsthereof.

A twenty-fourth embodiment which is the process of the twentiethembodiment wherein the TSAC further comprises a support.

A twenty-fifth embodiment which is the process of any of the twentieththrough twenty-fourth embodiments wherein the hydrocarbon adsorbercontacts at least a portion of the support, is distributed throughoutthe support, or combinations thereof.

A twenty-sixth embodiment which is the process of any of thetwenty-fourth through twenty-fifth embodiments wherein the supportcomprises a film, a foil, a mesh, a fiber cloth, a fiber cloth, a wovenfiber mesh, a woven wire mesh, a metallic woven wire mesh, a polymericmembrane, a surface treated material, a surface treated metal foil, awoven fiber cloth, or combinations thereof.

A twenty-seventh embodiment which is the process of any of thetwenty-fourth through twenty-sixth embodiments wherein the supportcomprises a thermally conductive polymer.

A twenty-eighth embodiment which is the process of any of thetwenty-fourth through twenty-seventh embodiments wherein the supportcomprises cellulose acetate, polyvinylpyrrolidone, or combinationsthereof.

A twenty-ninth embodiment which is the process of any of the twentieththrough twenty-eighth embodiments wherein the hollow tubes comprise athermally conductive material, a metal, aluminum, nickel, an alloy,stainless steel, thermally conductive polymers, polymeric materials,latexes, polyvinylidene chloride latex, carbon, glass, ceramics, orcombinations thereof.

A thirtieth embodiment which is the process of any of the twentieththrough twenty-ninth embodiments wherein the TSAC comprises a pluralityof hollow fiber contactors.

A thirty-first embodiment which is the process of any of the twentieththrough twenty-ninth embodiments wherein a cooling fluid passes throughat least a portion of the hollow tubes prior to and/or during (c)contacting the spent purge gas stream with the TSAC.

A thirty-second embodiment which is the process of the thirty-firstembodiment wherein the cooling fluid comprises water, tap water, processwater, an aqueous solution, or combinations thereof.

A thirty-third embodiment which is the process of any of the twentieththrough thirty-second embodiments wherein a heating fluid passes throughat least a portion of the hollow tubes during (d) heating the loadedTSAC.

A thirty-fourth embodiment which is the process of any of the firstthrough thirty-third embodiments wherein the heating fluid compriseswarm water, hot water, steam, or combinations thereof.

A thirty-fifth embodiment which is the process of any of the firstthrough thirty-fourth embodiments wherein the TSAC is characterized by acycle time of from about 10 seconds to about 1 hour.

A thirty-sixth embodiment which is a process for component separation ina polymer production system, comprising (a) separating a polymerizationproduct stream into a gas stream and a polymer stream, wherein thepolymer stream comprises polyethylene, ethylene and ethane; (b)contacting at least a portion of the polymer stream with nitrogen toyield a purged polymer stream and a spent purge gas stream, wherein thepurged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises nitrogen, ethylene, and ethane, wherein a pressureof the spent purge gas stream is from about 100 kPa to about 150 kPa,wherein ethylene is characterized by a partial pressure of less thanabout 10 kPa, and wherein ethane is characterized by a partial pressureof less than about 5 kPa; (c) contacting at least a portion of the spentpurge gas stream with a temperature swing adsorber contactor (TSAC)comprising a 4 A zeolite and a plurality of hollow tubes at about 20° C.to yield a loaded TSAC and a non-adsorbed gas stream, wherein at least aportion of the ethylene is adsorbed by the TSAC to yield TSAC-adsorbedethylene, wherein a portion of the ethane is adsorbed by the TSAC toyield TSAC-adsorbed ethane, wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane, and wherein the TSAC ischaracterized by an adsorption selectivity of ethylene versus ethane at20° C. of equal to or greater than about 5; (d) passing water at atemperature of about 50° C. through at least a portion of the hollowtubes of the loaded TSAC to yield a regenerated TSAC, desorbed ethyleneand desorbed ethane, wherein the desorbed ethylene comprises at least aportion of the TSAC-adsorbed ethylene, and wherein the desorbed ethanecomprises at least a portion of the TSAC-adsorbed ethane; and (e)contacting at least a portion of the 4 A zeolite of the regenerated TSACwith olefin-free isobutane to yield a recovered adsorbed gas streamcomprising isobutane, recovered ethylene and recovered ethane, whereinthe recovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.

A thirty-seventh embodiment which is the process of the thirty-sixthembodiment wherein a cooling fluid comprising water passes through atleast a portion of the hollow tubes prior to and/or during (c)contacting the spent purge gas stream with the TSAC.

A thirty-eighth embodiment which is a process for component separationin a polymer production system, comprising (a) separating apolymerization product stream into a gas stream and a polymer stream,wherein the polymer stream comprises a polymer, a first hydrocarbon anda second hydrocarbon; (b) contacting at least a portion of the polymerstream with a purge gas to yield a purged polymer stream and a spentpurge gas stream, wherein the purged polymer stream comprises thepolymer, and wherein the spent purge gas comprises purge gas, the firsthydrocarbon and the second hydrocarbon; (c) contacting at least aportion of the spent purge gas stream with a temperature swing adsorbercontactor (TSAC) to yield a loaded TSAC and a non-adsorbed gas stream,wherein at least a portion of the first hydrocarbon is adsorbed by theTSAC at a first temperature to yield TSAC-adsorbed first hydrocarbon,wherein a portion of the second hydrocarbon is adsorbed by the TSAC atthe first temperature to yield TSAC-adsorbed second hydrocarbon, whereinthe loaded TSAC comprises TSAC-adsorbed first hydrocarbon andTSAC-adsorbed second hydrocarbon, and wherein the TSAC is characterizedby an adsorption selectivity of first hydrocarbon versus secondhydrocarbon at the first temperature of equal to or greater than about5; (d) heating at least a portion of the loaded TSAC to a secondtemperature to yield a regenerated TSAC, desorbed first hydrocarbon anddesorbed second hydrocarbon, wherein the desorbed first hydrocarboncomprises at least a portion of the TSAC-adsorbed first hydrocarbon,wherein the desorbed second hydrocarbon comprises at least a portion ofthe TSAC-adsorbed second hydrocarbon, and wherein the second temperatureis greater than the first temperature by equal to or greater than about10° C.; and (e) contacting at least a portion of the regenerated TSACwith a sweeping gas stream to yield a recovered adsorbed gas stream,wherein the recovered adsorbed gas stream comprises a sweeping gas,recovered first hydrocarbon and recovered second hydrocarbon, whereinthe recovered first hydrocarbon comprises at least a portion of thedesorbed first hydrocarbon, and wherein the recovered second hydrocarboncomprises at least a portion of the desorbed second hydrocarbon.

A thirty-ninth embodiment which is a process for hydrocarbon recovery,comprising (a) providing a hydrocarbon stream comprising a firsthydrocarbon and a second hydrocarbon, wherein the hydrocarbon stream ischaracterized by a pressure of from about 100 kPa to about 200 kPa,wherein the first hydrocarbon is characterized by a partial pressure offrom about 1 kPa to about 20 kPa, and wherein the second hydrocarbon ischaracterized by a partial pressure of from about 0.1 kPa to about 10kPa; (b) contacting at least a portion of the hydrocarbon stream with atemperature swing adsorber contactor (TSAC) to yield a loaded TSAC and anon-adsorbed gas stream, wherein at least a portion of the firsthydrocarbon is adsorbed by the TSAC at a first temperature to yieldTSAC-adsorbed first hydrocarbon, wherein a portion of the secondhydrocarbon is adsorbed by the TSAC at the first temperature to yieldTSAC-adsorbed second hydrocarbon, wherein the loaded TSAC comprisesTSAC-adsorbed first hydrocarbon and TSAC-adsorbed second hydrocarbon,and wherein the TSAC is characterized by an adsorption selectivity offirst hydrocarbon versus second hydrocarbon at the first temperature ofequal to or greater than about 5; (c) heating at least a portion of theloaded TSAC to a second temperature to yield a regenerated TSAC,desorbed first hydrocarbon and desorbed second hydrocarbon, wherein thedesorbed first hydrocarbon comprises at least a portion of theTSAC-adsorbed first hydrocarbon, wherein the desorbed second hydrocarboncomprises at least a portion of the TSAC-adsorbed second hydrocarbon,and wherein the second temperature is greater than the first temperatureby equal to or greater than about 10° C.; and (d) contacting at least aportion of the regenerated TSAC with a sweeping gas stream to yield arecovered adsorbed gas stream, wherein the recovered adsorbed gas streamcomprises a sweeping gas, recovered first hydrocarbon and recoveredsecond hydrocarbon, wherein the recovered first hydrocarbon comprises atleast a portion of the desorbed first hydrocarbon, and wherein therecovered second hydrocarbon comprises at least a portion of thedesorbed second hydrocarbon.

A fortieth embodiment which is a process for ethylene recovery from adilute ethylene stream in a polyethylene production system, comprising(a) providing a dilute ethylene stream comprising ethylene and ethane,wherein a pressure of the dilute ethylene stream is from about 100 kPato about 150 kPa, wherein ethylene is characterized by a partialpressure of less than about 10 kPa, and wherein ethane is characterizedby a partial pressure of less than about 5 kPa; (b) contacting thedilute ethylene stream with a temperature swing adsorber contactor(TSAC) to yield a loaded TSAC and a non-adsorbed gas stream, wherein atleast a portion of the ethylene is adsorbed by the TSAC at a firsttemperature to yield TSAC-adsorbed ethylene, wherein a portion of theethane is adsorbed by the TSAC at the first temperature to yieldTSAC-adsorbed ethane, wherein the loaded TSAC comprises TSAC-adsorbedethylene and TSAC-adsorbed ethane, and wherein the TSAC is characterizedby an adsorption selectivity of ethylene versus ethane at the firsttemperature of equal to or greater than about 5; (c) heating at least aportion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, wherein the desorbed ethane comprises at least a portion ofthe TSAC-adsorbed ethane, and wherein the second temperature is greaterthan the first temperature by equal to or greater than about 10° C.; and(d) contacting at least a portion of the regenerated TSAC with asweeping gas stream to yield a recovered adsorbed gas stream, whereinthe recovered adsorbed gas stream comprises a sweeping gas, recoveredethylene and recovered ethane, wherein the recovered ethylene comprisesat least a portion of the desorbed ethylene, and wherein the recoveredethane comprises at least a portion of the desorbed ethane.

A forty-first embodiment which is a temperature swing adsorber contactorsystem comprising a temperature swing adsorption unit; wherein thetemperature swing adsorption unit comprises at least one temperatureswing adsorber contactor (TSAC) disposed therein; wherein the TSACcomprises a plurality of hollow tubes and a hydrocarbon adsorber,wherein the hollow tube comprises a hollow tube outer surface, whereinat least a portion of the hollow tube outer surface is in contact withthe hydrocarbon adsorber; wherein the TSAC comprises a support, whereinthe hydrocarbon adsorber contacts at least a portion of the support, isdistributed throughout the support, or combinations thereof; wherein thetemperature swing adsorption unit adsorbs at a first temperature,wherein the hydrocarbon adsorber adsorbs a first amount of a firsthydrocarbon characterized by a first partial pressure and a secondamount of a second hydrocarbon characterized by a second partialpressure to yield a loaded TSAC comprising a TSAC-adsorbed firsthydrocarbon and a TSAC-adsorbed second hydrocarbon; wherein thehydrocarbon adsorber has an adsorption selectivity of the firsthydrocarbon versus the second hydrocarbon at the first temperature ofequal to or greater than about 5; wherein the temperature swingadsorption unit regenerates at a second temperature, wherein the loadedTSAC is regenerated to yield a regenerated TSAC, a third amount of arecovered first hydrocarbon and a fourth amount of a recovered secondhydrocarbon; wherein the second temperature is greater than the firsttemperature by equal to or greater than about 10° C.; wherein a molarratio of the third amount to the first amount at the first partialpressure is from about 0.01 to about 1; and wherein a molar ratio of thefourth amount at the second partial pressure to the second amount isfrom about 0 to about 1.

A forty-second embodiment which is a process for ethylenepolymerization, comprising (a) polymerizing ethylene in a slurry loopreactor system to obtain a polymerization product stream; (b) separatinga polymerization product stream in a flash chamber into a gas stream anda polymer stream comprising polyethylene, ethylene and ethane; (c)contacting at least a portion of the polymer stream with a purge gas ina purge column to yield a purged polymer stream and a spent purge gasstream, wherein the purged polymer stream comprises polyethylene, andwherein the spent purge gas comprises nitrogen, ethylene, and ethane;(d) contacting at least a portion of the spent purge gas stream with atemperature swing adsorber contactor (TSAC) to yield a loaded TSAC and anon-adsorbed gas stream, wherein at least a portion of the ethylene isadsorbed by the TSAC at a first temperature to yield TSAC-adsorbedethylene, wherein a portion of the ethane is adsorbed by the TSAC at thefirst temperature to yield TSAC-adsorbed ethane, wherein the loaded TSACcomprises TSAC-adsorbed ethylene and TSAC-adsorbed ethane, and whereinthe TSAC is characterized by an adsorption selectivity of ethyleneversus ethane at the first temperature of equal to or greater than about5; (e) heating at least a portion of the loaded TSAC to a secondtemperature to yield a regenerated TSAC, desorbed ethylene and desorbedethane, wherein the desorbed ethylene comprises at least a portion ofthe TSAC-adsorbed ethylene, wherein the desorbed ethane comprises atleast a portion of the TSAC-adsorbed ethane, and wherein the secondtemperature is greater than the first temperature by equal to or greaterthan about 10° C.; and (f) contacting at least a portion of theregenerated TSAC with olefin-free isobutane to yield a recoveredadsorbed gas stream, wherein the recovered adsorbed gas stream comprisesisobutane, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.

A forty-third embodiment which is the process of the forty-secondembodiment, wherein at least a portion of the recovered adsorbed gasstream is recycled as a reagent for (a) polymerizing ethylene; whereinat least a portion of the non-adsorbed gas stream is separated into anitrogen stream and an isobutane and ethane stream; wherein at least aportion of the nitrogen stream is used as the purge gas for (c)contacting the polymer stream; wherein at least a portion of theisobutane and ethane stream is distilled into a light distillationbottoms stream comprising olefin-free isobutane; and wherein at least aportion of the light distillation bottoms stream is used for (f)contacting the regenerated TSAC.

While embodiments of the disclosure have been shown and described,modifications thereof can be made without departing from the spirit andteachings of the invention. The embodiments and examples describedherein are exemplary only, and are not intended to be limiting. Manyvariations and modifications of the invention disclosed herein arepossible and are within the scope of the invention.

At least one embodiment is disclosed and variations, combinations,and/or modifications of the embodiment(s) and/or features of theembodiment(s) made by a person having ordinary skill in the art arewithin the scope of the disclosure. Alternative embodiments that resultfrom combining, integrating, and/or omitting features of theembodiment(s) are also within the scope of the disclosure. Wherenumerical ranges or limitations are expressly stated, such expressranges or limitations should be understood to include iterative rangesor limitations of like magnitude falling within the expressly statedranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4,etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example,whenever a numerical range with a lower limit, R_(l), and an upperlimit, R_(u), is disclosed, any number falling within the range isspecifically disclosed. In particular, the following numbers within therange are specifically disclosed: R=R_(l)+k*(R_(u)−R_(l)), wherein k isa variable ranging from 1 percent to 100 percent with a 1 percentincrement, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5percent, . . . 50 percent, 51 percent, 52 percent . . . 95 percent, 96percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover,any numerical range defined by two R numbers as defined in the above isalso specifically disclosed. Use of the term “optionally” with respectto any element of a claim means that the element is required, oralternatively, the element is not required, both alternatives beingwithin the scope of the claim. Use of broader terms such as comprises,includes, and having should be understood to provide support fornarrower terms such as consisting of, consisting essentially of, andcomprised substantially of.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present invention. Thus, the claims are a further description andare an addition to the detailed description of the present invention.The disclosures of all patents, patent applications, and publicationscited herein are hereby incorporated by reference.

We claim:
 1. A process for component separation in a polymer productionsystem, comprising: (a) separating a polymerization product stream intoa gas stream and a polymer stream, wherein the polymer stream comprisespolyethylene, ethylene and ethane; (b) contacting at least a portion ofthe polymer stream with a purge gas to yield a purged polymer stream anda spent purge gas stream, wherein the purged polymer stream comprisespolyethylene, and wherein the spent purge gas comprises purge gas,ethylene, and ethane; (c) contacting at least a portion of the spentpurge gas stream with a temperature swing adsorber contactor (TSAC) toyield a loaded TSAC and a non-adsorbed gas stream, wherein at least aportion of the ethylene is adsorbed by the TSAC at a first temperatureto yield TSAC-adsorbed ethylene, wherein a portion of the ethane isadsorbed by the TSAC at the first temperature to yield TSAC-adsorbedethane, and wherein the loaded TSAC comprises TSAC-adsorbed ethylene andTSAC-adsorbed ethane; (d) heating at least a portion of the loaded TSACto a second temperature to yield a regenerated TSAC, desorbed ethyleneand desorbed ethane, wherein the desorbed ethylene comprises at least aportion of the TSAC-adsorbed ethylene, and wherein the desorbed ethanecomprises at least a portion of the TSAC-adsorbed ethane; and (e)contacting at least a portion of the regenerated TSAC with a sweepinggas stream to yield a recovered adsorbed gas stream, wherein therecovered adsorbed gas stream comprises sweeping gas, recovered ethyleneand recovered ethane, wherein the recovered ethylene comprises at leasta portion of the desorbed ethylene, and wherein the recovered ethanecomprises at least a portion of the desorbed ethane.
 2. The process ofclaim 1, wherein the TSAC is characterized by an adsorption selectivityof ethylene versus ethane at the first temperature of equal to orgreater than about
 5. 3. The process of claim 1, wherein the secondtemperature is greater than the first temperature by equal to or greaterthan about 10° C.
 4. The process of claim 1, wherein the ethylene of thespent purge gas stream is characterized by a partial pressure of fromabout 1 kPa to about 20 kPa.
 5. The process of claim 1, wherein theethane of the spent purge gas stream is characterized by a partialpressure of from about 0.1 kPa to about 10 kPa.
 6. The process of claim1, wherein a molar ratio of desorbed ethylene to TSAC-adsorbed ethyleneis from about 0.01 to about
 1. 7. The process of claim 1, wherein (c)contacting the spent purge gas stream occurs in a first temperatureswing adsorption unit and (d) heating of the loaded TSAC and (e)contacting the regenerated TSAC occurs in a second temperature swingadsorption unit, wherein the first temperature swing adsorption unit andthe second temperature swing adsorption unit are operated in parallel.8. The process of claim 1, wherein (d) heating the loaded TSAC and (e)contacting the regenerated TSAC occur concurrently within the sametemperature swing adsorption unit.
 9. The process of claim 1, whereinthe TSAC comprises a plurality of hollow tubes and a hydrocarbonadsorber, wherein the hollow tube comprises a hollow tube outer surface,wherein at least a portion of the hollow tube outer surface is incontact with the hydrocarbon adsorber.
 10. The process of claim 9,wherein the hydrocarbon adsorber comprises a zeolite, metal-organicframeworks, carbon, molecular sieve carbon, zeolitic imidazolateframeworks, or combinations thereof.
 11. The process of claim 9, whereinthe hydrocarbon adsorber comprises a 4 A molecular sieve.
 12. Theprocess of claim 10, wherein the zeolite comprises a cationic zeolite,an aluminosilicate, an alkali metal aluminosilicate, a sodiumaluminosilicate, an X zeolite, a NaX zeolite, a 13X zeolite, an Azeolite, a NaA zeolite, KA zeolite, NaCaA zeolite, or combinationsthereof.
 13. The process of claim 9, wherein the TSAC further comprisesa support, wherein the hydrocarbon adsorber contacts at least a portionof the support, is distributed throughout the support, or combinationsthereof.
 14. The process of claim 13, wherein the support comprises afilm, a foil, a mesh, a fiber cloth, a fiber cloth, a woven fiber mesh,a woven wire mesh, a metallic woven wire mesh, a polymeric membrane, asurface treated material, a surface treated metal foil, a woven fibercloth, or combinations thereof.
 15. The process of claim 9, wherein thehollow tubes comprise a thermally conductive material, a metal,aluminum, nickel, an alloy, stainless steel, thermally conductivepolymers, polymeric materials, latexes, polyvinylidene chloride latex,carbon, glass, ceramics, or combinations thereof.
 16. The process ofclaim 9, wherein the TSAC comprises a plurality of hollow fibercontactors.
 17. The process of claim 1, wherein the TSAC ischaracterized by a cycle time of from about 10 seconds to about 1 hour.18. A process for ethylene recovery from a dilute ethylene stream in apolyethylene production system, comprising: (a) providing a diluteethylene stream comprising ethylene and ethane, wherein a pressure ofthe dilute ethylene stream is from about 100 kPa to about 150 kPa,wherein ethylene is characterized by a partial pressure of less thanabout 10 kPa, and wherein ethane is characterized by a partial pressureof less than about 5 kPa; (b) contacting the dilute ethylene stream witha temperature swing adsorber contactor (TSAC) to yield a loaded TSAC anda non-adsorbed gas stream, wherein at least a portion of the ethylene isadsorbed by the TSAC at a first temperature to yield TSAC-adsorbedethylene, wherein a portion of the ethane is adsorbed by the TSAC at thefirst temperature to yield TSAC-adsorbed ethane, wherein the loaded TSACcomprises TSAC-adsorbed ethylene and TSAC-adsorbed ethane, and whereinthe TSAC is characterized by an adsorption selectivity of ethyleneversus ethane at the first temperature of equal to or greater than about5; (c) heating at least a portion of the loaded TSAC to a secondtemperature to yield a regenerated TSAC, desorbed ethylene and desorbedethane, wherein the desorbed ethylene comprises at least a portion ofthe TSAC-adsorbed ethylene, wherein the desorbed ethane comprises atleast a portion of the TSAC-adsorbed ethane, and wherein the secondtemperature is greater than the first temperature by equal to or greaterthan about 10° C.; and (d) contacting at least a portion of theregenerated TSAC with a sweeping gas stream to yield a recoveredadsorbed gas stream, wherein the recovered adsorbed gas stream comprisesa sweeping gas, recovered ethylene and recovered ethane, wherein therecovered ethylene comprises at least a portion of the desorbedethylene, and wherein the recovered ethane comprises at least a portionof the desorbed ethane.
 19. A process for ethylene polymerization,comprising: (a) polymerizing ethylene in a slurry loop reactor system toobtain a polymerization product stream; (b) separating a polymerizationproduct stream in a flash chamber into a gas stream and a polymer streamcomprising polyethylene, ethylene and ethane; (c) contacting at least aportion of the polymer stream with a purge gas in a purge column toyield a purged polymer stream and a spent purge gas stream, wherein thepurged polymer stream comprises polyethylene, and wherein the spentpurge gas comprises nitrogen, ethylene, and ethane; (d) contacting atleast a portion of the spent purge gas stream with a temperature swingadsorber contactor (TSAC) to yield a loaded TSAC and a non-adsorbed gasstream, wherein at least a portion of the ethylene is adsorbed by theTSAC at a first temperature to yield TSAC-adsorbed ethylene, wherein aportion of the ethane is adsorbed by the TSAC at the first temperatureto yield TSAC-adsorbed ethane, wherein the loaded TSAC comprisesTSAC-adsorbed ethylene and TSAC-adsorbed ethane, and wherein the TSAC ischaracterized by an adsorption selectivity of ethylene versus ethane atthe first temperature of equal to or greater than about 5; (e) heatingat least a portion of the loaded TSAC to a second temperature to yield aregenerated TSAC, desorbed ethylene and desorbed ethane, wherein thedesorbed ethylene comprises at least a portion of the TSAC-adsorbedethylene, wherein the desorbed ethane comprises at least a portion ofthe TSAC-adsorbed ethane, and wherein the second temperature is greaterthan the first temperature by equal to or greater than about 10° C.; and(f) contacting at least a portion of the regenerated TSAC witholefin-free isobutane to yield a recovered adsorbed gas stream, whereinthe recovered adsorbed gas stream comprises isobutane, recoveredethylene and recovered ethane, wherein the recovered ethylene comprisesat least a portion of the desorbed ethylene, and wherein the recoveredethane comprises at least a portion of the desorbed ethane.
 20. Theprocess of claim 19, wherein at least a portion of the recoveredadsorbed gas stream is recycled as a reagent for (a) polymerizingethylene; wherein at least a portion of the non-adsorbed gas stream isseparated into a nitrogen stream and an isobutane and ethane stream;wherein at least a portion of the nitrogen stream is used as the purgegas for (c) contacting the polymer stream; wherein at least a portion ofthe isobutane and ethane stream is distilled into a light distillationbottoms stream comprising olefin-free isobutane; and wherein at least aportion of the light distillation bottoms stream is used for (f)contacting the regenerated TSAC.